2017 MTV Video Music Awards – Arrivals – Inglewood, California, U.S., 27/08/2017 - Demi Lovato. REUTERS/Danny Moloshok 

2017 MTV Video Music Awards – Arrivals – Inglewood, California, U.S., 27/08/2017 - Demi Lovato. REUTERS/Danny Moloshok 

2017 MTV Video Music Awards – Arrivals – Inglewood, California, U.S., 27/08/2017 - Demi Lovato. REUTERS/Danny Moloshok 

2017 MTV Video Music Awards – Arrivals – Inglewood, California, U.S., 27/08/2017 - Demi Lovato. REUTERS/Danny Moloshok 

2017 MTV Video Music Awards – Arrivals – Inglewood, California, U.S., 27/08/2017 - Demi Lovato. REUTERS/Danny Moloshok 

Boxing - Floyd Mayweather Jr. vs Conor McGregor - Las Vegas, USA - August 26, 2017 Demi Lovato sings the national anthem before the fight REUTERS/Steve Marcus 

Boxing - Floyd Mayweather Jr. vs Conor McGregor - Las Vegas, USA - August 26, 2017 Demi Lovato prepares to sing the national anthem before the fight REUTERS/Steve Marcus 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs on ABC's 'Good Morning America' show in New York City, U.S., August 18, 2017. REUTERS/Brendan McDermid 

Singer Demi Lovato performs during the 16th Mawazine World Rhythms International Music Festival in Rabat, Morocco May 19, 2017. REUTERS/Youssef Boudlal 

Singer Demi Lovato performs during the 16th Mawazine World Rhythms International Music Festival in Rabat, Morocco May 19, 2017. REUTERS/Youssef Boudlal 

Singer Demi Lovato performs during the 16th Mawazine World Rhythms International Music Festival in Rabat, Morocco May 19, 2017. REUTERS/Youssef Boudlal 

Singer Demi Lovato performs during the 16th Mawazine World Rhythms International Music Festival in Rabat, Morocco May 19, 2017. REUTERS/Youssef Boudlal 

Singer Demi Lovato performs during the 16th Mawazine World Rhythms International Music Festival in Rabat, Morocco May 19, 2017. REUTERS/Youssef Boudlal 

Demi Lovato attends the WE Day event in Los Angeles, California, U.S., April 27, 2017. REUTERS/Phil McCarten 

Demi Lovato attends the WE Day event in Los Angeles, California, U.S., April 27, 2017. REUTERS/Phil McCarten 

Singer Demi Lovato arrives for the Time 100 Gala in the Manhattan borough of New York, New York, U.S. April 25, 2017. REUTERS/Carlo Allegri 

Singer Demi Lovato arrives for the Time 100 Gala in the Manhattan borough of New York, New York, U.S. April 25, 2017. REUTERS/Carlo Allegri 

Singer Demi Lovato arrives for the Time 100 Gala in the Manhattan borough of New York, New York, U.S. April 25, 2017. REUTERS/Carlo Allegri 

(L-R) Singers Little Big Town, Demi Lovato, Andra Day and Tori Kelly perform "Stayin' Alive" on stage during he Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

(L-R) Singers Little Big Town, Demi Lovato, Andra Day and Tori Kelly perform "Stayin' Alive" on stage during the Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

Singer Demi Lovato performs a medley on stage the Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

Singer Demi Lovato performs a medley on stage during the Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

Singer Demi Lovato performs "If I Can't Have You" during the taping of the Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

Singer Demi Lovato performs on stage during the Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

Singer Demi Lovato performs "If I Can't Have You" during the taping of the Stayin' Alive: A Grammy Salute to the Music of the Bee Gees in Los Angeles, California, U.S., February 14, 2017. The tribute aired Sunday, April 16, 2017 on CBS. Picture taken February 14, 2017. REUTERS/Mario Anzuoni 

Actor Demi Lovato arrives at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Cast members including from left to right, Meghan Trainor (obscured), Ariel Winter, Danny Pudi, Jack McBrayer, Demi Lovato, Joe Manganiello and the smurf character Papa Smurf arrive atop a tourist sightseeing bus at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Cast members, from left to right, Danny Pudi, Joe Manganiello, Meghan Trainor, Demi Lovato, Ariel Winter, Jack McBrayer and Jeff Dunham pose with Smurf characters at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Cast members, from left to right, Danny Pudi, Joe Manganiello, Meghan Trainor, Demi Lovato, Ariel Winter, Jack McBrayer and Jeff Dunham pose with Smurf characters at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, poses with the Smurfette character (L) who she voices in the film "Smurfs: The Lost Village" and Papa Smurf (R) at it's premiere in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, poses with the Smurfette character who she voices in the film "Smurfs: The Lost Village" at it's premiere in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, poses with the Smurfette character who she voices in the film "Smurfs: The Lost Village" at it's premiere in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, poses with the Smurfette character who she voices in the film "Smurfs: The Lost Village" at it's premiere in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actors Meghan Trainor (L), Demi Lovato (C) and Ariel Winter (R) pose at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

From left to right, actors Meghan Trainor, Demi Lovato, Ariel Winter and Jack McBrayer pose at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, who voices the Smurfette character, poses at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

Actor Demi Lovato, Actor Joe Manganiello, and Papa Smurf character wave from a bus as they arrive at the premiere of the film "Smurfs: The Lost Village" in Culver City, California, April 1, 2017. REUTERS/Danny Moloshok 

2017 Kids' Choice Awards - Show - Los Angeles, California, U.S., 11/03/2017 - Singer Demi Lovato is "slimed." REUTERS/Mario Anzuoni 

2017 Kids' Choice Awards - Show - Los Angeles, California, U.S., 11/03/2017 - Singer Demi Lovato is "slimed." REUTERS/Mario Anzuoni 

2017 Kids' Choice Awards - Show - Los Angeles, California, U.S., 11/03/2017 - Singer Demi Lovato is "slimed." REUTERS/Mario Anzuoni 

2017 Kids' Choice Awards - Show - Los Angeles, California, U.S., 11/03/2017 - Singer Demi Lovato is "slimed." REUTERS/Mario Anzuoni 

2017 Kids’ Choice Awards – Show - Los Angeles, California, U.S., 11/3/2017 - Singer Demi Lovato gets slimed. REUTERS/Mario Anzuoni 

2017 Kids' Choice Awards - Show - Los Angeles, California, U.S., 11/03/2017 - Singer Demi Lovato is "slimed." REUTERS/Mario Anzuoni 

2017 Kids' Choice Awards - Show - Los Angeles, California, U.S., 11/03/2017 - Singer Demi Lovato is "slimed." REUTERS/Mario Anzuoni TPX IMAGES OF THE DAY