Stamos is set to play dentist Carl Howell. Gleeks will recall that his character was referenced during the June 8 season one finale of "Glee" when Emma told Will that she was dating the dentist.
"I started watching the show when they goofed on me and fell in love with 'Glee.' I find it to be a celebration of diversity and I'm proud to be joining that whole extremely talented team," Stamos said.
Earlier this season Emma said of Stamos: "They say it takes certainty more than talent to make a star. I mean, look at John Stamos."
Stamos is best known for his roles on the television series "Full House" and "ER." On Broadway, he has stepped into the productions of How to Succeed in Business Without Really Trying, Cabaret, Nine and portrayed Albert Peterson in the Roundabout Theatre Company revival of Bye Bye Birdie last fall.
The second season of "Glee" will return Tuesdays this fall in the 8-9 PM ET time slot.
Matthew Morrison (South Pacific, The Light in the Piazza) stars as Spanish teacher Will Schuester with Spring Awakening's Lea Michele as glee club Broadway baby Rachel Berry with fellow glee club members Jenna Ushkowitz as Tina, Chris Colfer as Kurt, Kevin McHale as Artie, Cory Monteith as Finn Hudson and Amber Riley as Mercedes Jones.
The ensemble cast also includes Jane Lynch as cheerleading coach Sue Sylvester, Jessalyn Gilsig as Terri Schuester, Jayma Mays as teacher Emma Pillsbury, Dianna Agron as cheerleader Quinn and Mark Salling as football player Puck.