Mark-Paul Gosselaar Gossip

A sneak peek at Dustin Diamond's "shocking" new Saved By the Bell tell-all, Behind the Bell, contains claims of drugs, sex and even steroid use.

Yes, Double-D claims that co-star Mark-Paul Gosselaar, who portrayed Bayside High hunk Zack Morris, was juicing on set of the popular TV show.

Specifically, he alleges Gosselaar began using steroids before production started on the short-lived Saved by the Bell: The College Years spinoff.

"[Mark-Paul] suddenly exploded with manliness, loading 25 pounds of muscle on his once-scrawny frame in, oh, about a month," writes Dustin Diamond, 32, who is, perhaps for this very reason, not in touch with any of his former co-stars.

Gosselaar, who dismissed the book and wanted its author banned from the Saved By the Bell reunion in August, dismissed Screech's new claims:

"We weren't in rehab and Mr. Belding wasn't my crack dealer,” he said.

Dustin Diamond also says the Saved By the Bell cast got stoned a lot.

"I could smell a certain type of 'smoke,' wafting from from the crack" underneath his cast mates' dressing rooms, says Diamond. Ooh, shocker.

The failed stand-up comic and grotesque sex tape purveyor, who filed for bankruptcy in 2001 and has myriad financial problems continuing to the present day, says his co-stars frequently hooked up off-camera as well as on it.

"If Kelly [Tiffani Thiessen] was interested in Slater [Mario Lopez] one week, backstage there was a lot going on in Mario [Lopez]'s room," he says.

"Then, if Jessie [Elizabeth Berkley] kissed Zack, then you know Elizabeth Berkley is going in Mark-Paul's room." Another staggering allegation.

Basically, Dustin Diamond's book is neither scandalous nor interesting based on these snippets. Give us some real dirt or get lost, D-squared.

The nine of you old enough to remember Saved By the Bell will appreciate this.

Appearing on Late Night With Jimmy Fallon to promote his new TNT show, Raising the Bar, Mark-Paul Gosselaar appeared in character ... as Zack Morris.

"I had to change my name to Mark-Paul Gosselaar because there was already a Zack Morris in SAG," Zack explained to the lame host, who played along.

Zack / Mark-Paul went on to reflect on his amazing SATs, his terrific summer working at the Malibu Sands and his ill-fated marriage (!) to Kelly Kapowski.

He then arranged a class reunion (as did Jessie Spano, via circa 1991 cell phone) and even joined the Late Night band for a number as "Zack Attack."

Check out this blast from the Saturday morning past below ...