Art imitates life for Glee star Lea Michele.
A source tells Us Weekly the actress (who plays uptight show standout Rachel Berry), 23, is a diva on the set of the Fox show, which airs its season finale Tuesday night.
"Lea acts like she's better than the rest of the cast," says the insider. "But the thing is, she legitimately is."
Another set source says, "She's sweet, but she has her moments."
Apt to boss around makeup artists and other crew members, "She has very clear ideas about what she wants to do and how she wants to look. I think she's just Type-A, like her character."
A second pal points out that Lea has "always wanted to be a star," and, in a classic Hollywood move, "she has become super-strict about her diet. She is a vegan now and says she hasn't eaten cheese in a year!"'
Michele -- who admitted on The Oprah Winfrey Show she's more like her character than any of her co-stars -- even "sings along to her own songs on the radio."
At a May 24 cast dinner at Chicago's Sunda, she was the only star who refused to sign autographs for fans. After it was reported she snapped at photographer Patrick McMullan for asking her name at the Time 100 party, she Twittered that it was a "silly joke."
Still, the cast has bonded working 14-hour days.
"We've become so close, Dianna Agron, 24, who plays pregnant cheerleader Quinn Fabray, tells Us. "We're like a family."
Tell Us: Will you watch the finale tonight?