"It's one of the hardest things, to be a bastard for two hours and 40 minutes," Stamos tells PEOPLE. "It's exhausting."
"I'm not used to that as an actor, to make people not like me," he says. "I spent 30 years doing the opposite! But I know that I'm not doing the piece justice or the character justice if I don't lean into making him the snake that he is."
Stamos, 49, stars in the political satire (which ends its run Sept. 9 and will include a benefit performance for his charity, Project Cuddle Sept. 7) alongside James Earl Jones, Kristin Davis, John Larroquette and Cybill Shepherd. And he names the Broadway play among his top career accomplishments.
"This show reinvigorated my love for theater. It's magic. ... I don't remember the last time I felt like this."
The actor – who's had memorable roles on ER, Glee and several TV movies and Broadway shows since his Full House days – does reveal that he had a tough time with his character's southern accent in the play. "I just don't have a natural ear for accents; I worked on it so hard," he says.
Which got us thinking ... what other confessions might this star (who can even make Greek yogurt sexy) have to get off his chest? Spill it, Stamos …
He Really Digs James Earl Jones"In the very little rehearsal I had with him was we instantly became fond of each other," Stamos says of Jones, whom he calls "my personal hero." But after playing it cool, "I gave up about a month ago and now I follow him around the theater," adds the actor with a laugh. "I'm always hanging out in his dressing room."
He also bonded with Broadway first-timer Davis, who leaned on Stamos in her debut. "It was funny because I was Mr. Rock around her, trying to be really calm, and someone she could lean on and feel safe with on stage," says Stamos. "Come the first night, I was a wreck and she was cool as a cucumber."
He's Addicted to Twitter"I spend way too much time on it," he admits. "It's a double-edged sword: it's so great to be in touch with your fans, but the trap is that you're not really experiencing something. You're thinking, 'How am I going to Tweet this?' "
Case in point? While decompressing after a recent show in his dressing room, "Bill O'Reilly and Perez Hilton came to my door," says Stamos. "Sounds like the beginning of a joke. It was pretty interesting negotiating the two of them. And all I [cared] about was getting a picture for Twitter." (If you're on a desktop, see the photo in the carousel above.)