Lovato's appearance will mark the first time there's ever been an international performance on the TV special, which will also feature remote appearances by Lucy Hale, Jason Derulo and Panic! at the Disco in New Orleans, as well as a performance by Lionel Richie from Las Vegas.
Lisa Lutoff-Perlo, President and CEO of Celebrity Cruises, revealed that this is "a momentous occasion" for the cruise line, as this is "the first time four ships will be docked in one port for a unique musical event, our first holiday concert and our first time on Dick Clark's New Year's Rockin' Eve with Ryan Seacrest 2017."
"Celebrating New Year's with Demi Lovato in St. Maarten, alongside thousands of our guests and her fans, will make for an event they won't soon forget," she added. "We are excited to share this milestone moment with those celebrating at home."
Seacrest will be hosting the 45th anniversary of "America's biggest celebration of the year" live from New York City's Times Square for the eleventh year. The special will also feature live on-site reporting from Jenny McCarthy, with performances in Times Square by Mariah Carey, DNCE, Thomas Rhett and Gloria Estefan with the cast of her Broadway musical, On Your Feet!
Meanwhile, at the Billboard Holiday Party, Fergie will be playing double duty as host and performer, with additional performances by Fifth Harmony featuring Kid Ink and Ty Dolla $ign, Flo Rida featuring Mary Kate, G-Eazy featuring Bebe Rexha, Martin Garrix (also with Rexha), Niall Horan, John Legend, Lukas Graham, Shawn Mendes, Mike Posner, Emeli Sande, Hailee Steinfeld and Alessia Cara.
The New Year's celebration begins live at 8 p.m. ET/PT on ABC.