Gretchen Wieners isn't the only one full of secrets, because "Mean Girls" star Daniel Franzese was hiding one of his own: He's gay.

Though he played "too gay to function" Damian in the film (Janice's words, not ours!), the actor himself was not out in real life -- and was even photographed kissing his female date on the red carpet at the movie's premiere (below).

"I'm happy to be free and honest with myself and my fans," he tells toofab of his decision to come out now, 10 years later. "It feels like a backpack full of bricks has been lifted off of me. The outpouring of support has been overwhelming and I urge anyone else in the industry who is contemplating doing this, to do it. It feels great."

In a letter he penned to his on-screen character posted over at /bent earlier today, Franzese says he had trouble landing "masculine" roles after playing a gay teen -- so he hid his sexuality from the public eye until now.

"While my reps usually lied to protect me, my friends and family all knew the truth but now it's time everyone does," he wrote in the letter. "Perhaps this will help someone else. I’m not afraid anymore. Of Hollywood, the closet or mean girls."

Daniel tells toofab he's excited to be the Celebrity Grand Marshall at the Portland Gay Pride Parade in June ... and he's single!

Now, about that reunion ...

Though the cast and crew were planning to get together for a big 10 year anniversary screening in New York next month -- something Lindsay Lohan and Tina Fey both hinted at in the past -- Daniel tells us it's been canceled. 

Scheduling conflicts with the cast made it too difficult to pull off.

So not fetch!