Leah Remini Offered Millions For Scientology Tell-All

Leah Remini is the hottest commodity in the publishing world. The former Scientologist is being offered millions of dollars for a tell-all memoir, RadarOnline.com is exclusively reporting.

"Everybody wants the Remini book," a top publishing executive tells Radar.  "If she'll tell all about her years in Scientology, her interactions with other celebs in the religion, and what she went through in getting out -- well, the sky's the limit."

The source tells us Remini could almost "write her own ticket" if she'll agree to open up.

She could join the ranks of some of the biggest book advances in history, including the $7 million paid to Keith Richards and the $6 million paid to Tina Fey  .

Bill and Hillary Clinton received the all-time biggest book advances -- $15 million for the former president in 2004, $14 million for Hillary's autobiography.

Could Leah reach a number that high?

It's not impossible, says our insider.  "If she were to lift the lid off how the church really operates under David Miscavige and how Tom Cruise fits in, that would up the ante."

The book could not appear to be salacious or gossipy, the source says.  "It would have to be a thought-provoking, sometimes funny, sometimes scary, sometimes sad look at Hollywood and Scientology that reveals information never previously known to the public.