'The Voice' announces 'mega mentor' for season 17

Season 17 of "The Voice" just got a whole lot more star power!

The NBC singing competition announced on Monday that Taylor Swift will join the upcoming season as a so-called mega-mentor.

In a fun video posted to Twitter, coaches John Legend and Blake Shelton play dumb as they discussed the fact that "one of the most successful people in music" will be part of the new season.

"I hear we have a mega mentor," Legend says.

"I don't know who it is," Shelton replies. "I know it's supposed to be a big star."

It's then that Swift casually walks out of the trailer behind them and says hi to the coaching duo, who are joined by Gwen Stefani and Kelly Clarkson as this season's coaches.

SEE ALSO: Expect real-life couple Gwen Stefani and Blake Shelton to 'spar' on 'The Voice' this season

Deadline reports that Swift, who released her seventh album, "Lover," last month, will mentor contestants from all four coaches' teams during the show's Knockout Rounds, which air in late October. This is the singer's second appearance as a so-called mega mentor on the show, having previously worked with contestants on season 7. She also performed during the season 16 finale in the spring.

Normani, Darius Rucker, will.i.am and Usher will also serve as mentors to individual teams this season. This will be the first season of "The Voice" without Adam Levine as a coach.

Season 17 of "The Voice" premieres on NBC on Monday, September 23 at 8 p.m. EST.