Quadruple chair turn! A source reveals in the new issue of Us Weekly that The Voice has landed four megastar guests for Season 9.

“Selena Gomez will be Gwen Stefani’s mentor. John Fogerty will be Adam Levine’s. Brad Paisley is Blake Shelton’s, and Missy Elliott is Pharrell [Williams]’s,” the source reveals.

Gomez, 23, was a backstage favorite.

“She was surprisingly amazing as a mentor even though she’s so young,” the source reveals of the “Good for You” songstress. “She exceeded everyone’s expectations.”

Levine, 36, “always wanted to work with Fogerty,” the insider tells Us, and considers the 70-year-old a “legend.”

“John performed at The Voice finale, and that’s when Adam asked him to come back this season as a mentor,” the source confirms.

Shelton, 39, needed 42-year-old Paisley to be more than just a mentor this season.

“Brad was a good friend to Blake, and it was great for Blake to have him there — especially considering everything Blake is going through,” the source adds. As previously reported by Us, Shelton and his wife of four years, Miranda Lambert, announced their divorce on July 20.

Mentors enter the ring during The Voice’s battle rounds, right after blind auditions. Gomez, Fogerty, Paisley, and Elliott join an alumni class of award-winning performers who’ve acted as mentors for up-and-coming talent of the show. Other bold names who’ve had the honor of guiding contestants in past seasons include Lionel Richie, Ellie Goulding, Meghan Trainor, Stevie Nicks, Gavin Rossdale, and Alicia Keys.

NBC’s The Voice returns on Sept. 21 at 8 p.m. ET.