The 'Independence Day' actor will team up with Broadway star Brian Stokes to play the adoptive parents of the character - played by Lea Michele - and the pair will sing a duet together on a special Valentine's Day (14.02.12) episode, TVLine has confirmed.
Although Rachel's parents have often been discussed in the musical TV show, they have never been seen before.
Meanwhile, Corey Monteith - who plays Finn Hudson - has confirmed his character will return despite having graduated from William McKinley High School at the end of the season.
He said: "I will be back. I will be graduating from William McKinley High School and I will be returning to 'Glee' in season four."
Corey was particularly excited to get to propose to on-screen girlfriend Rachel recently.
He added to E! News: "Finn has some real, real feelings for Rachel that lead toward it but I think he's also trying to hang on to something. He's trying to keep the love locked down. You know what I'm saying?
"He's trying to hang on to what he considers to be the one good thing in life he has going, which is his relationship with Rachel. He feels like it's his.
"He's kind of down on himself because everyone knows what they're doing; everyone knows where they're going and he doesn't. And the one thing he knows he wants is Rachel. He's in love with her."