Dustin Diamond: Mark-Paul Gosselaar Used Steroids

First a sex tape, now a shocking tell-all? What has become of Screech?

Dustin Diamond, 32, who played Saved By the Bell's adorable dork Screech Powers for much of the 1990s, has released a preview of his new book, Behind the Bell, in which the former child star claims that sex and drugs were prevalent on the set of the teen sitcom, according to Us.

Screech tattles on fellow Saved by the Bell stars

"I could smell a certain 'smoke,' wafting from the crack" from under his castmates' dressing rooms, says Diamond.

He also claims Mark-Paul Gosselaar, aka Bell's Zack Morris, used steroids before production of the short-lived Saved by the Bell: The College Years, in 1994.

Mark-Paul Gosselaar reprises Zack Morris on Jimmy Fallon

"He suddenly exploded with manliness, loading 25 pounds of muscle on his once-scrawny frame in, oh, about a month," says Diamond.

Diamond, who no longer keeps in touch with his former co-stars, also alleges his castmates would hook up off-camera.

"If Kelly [Tiffani Thiessen] was interested in Slater [Mario Lopez] one week, then backstage there was a lot going between them in Mario's room," Dustin says. "Then, if Jessie [Elizabeth Berkley] kisses Zack, then you know Elizabeth Berkley is going in Mark-Paul's room."

The Celebrity Fit Club alum, who filed for bankruptcy in 2001 and released his own sex tape in 2006, also claims Thiessen used guys to further her career and Mario Lopez was a serial womanizer.

Representatives for Gosselaar, Thiessen, Lopez, Berkley and Lark Voorhies (who played Lisa) did not immediately return calls to TVGuide.com.

Do you believe Diamond's claims? Or better yet, do you care?