Jason Priestley Jason Priestley

What happens in Beverly Hills most certainly does not stay in Beverly Hills.

In a new tell-all memoir, former Beverly Hills, 90210 star Jason Priestley offers juicy tidbits about his former co-stars on the hit show, as well as life as a young heartthrob living in Hollywood.

The revelations in the book, according to The Hollywood Reporter include tales of Shannen Doherty's diva behavior and Priestley deciding to put a vulgar spin on the famous line "Donna Martin graduates" as a joke during filming. Here's a breakdown:

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-Doherty "really and truly did not give a s---," Priestley writes. Doherty's diva behavior eventually led showrunner Aaron Spelling to fire her — and while she and Priestley played twins Brandon and Brenda Walsh on the show, their closeness didn't extend off-screen. "It was a very cool attitude, until it wasn't," Priestley recalls of Doherty's behavior.

-Priestley and Brad Pitt became best friends after they shared a bed. (No, not in that way.) The two met when Pitt was crashing with Priestley's roommate in North Hollywood, and Priestley came home to find Pitt asleep in his bed. "We lived on ramen noodles and generic beer — the kind that came in white cans labeled BEER — and Marlboro Light cigarettes," Priestley writes of their bromance.

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-Without naming names, Priestley confirms that "various combinations of [cast members] slept with each other over the years." He describes his own romance with co-star Christine Elise as "my first full-fledged adult relationship."

-Priestley has distanced himself from Tori Spelling since she married Dean McDermott — and holds a grudge about the fact that Spelling sold her invitation to Priestley's 2005 wedding for $5 at a yard sale. The producers of Tori and Dean's ubiquitous show do make a point of asking me to appear on every iteration. So far I haven't been able to find the time," he writes sarcastically.

-In what is perhaps the show's most-cited episode, the crowd chanting in support of Spelling's character are actually chanting "Donna Martin masturbates!," not "Donna Martin graduates!" The prank was Priestley's idea. "I knew they were going to go back and re-loop this dialogue anyway," he notes.

Revisit episodes of 90210 here. What do you think of Priestley's stories?