E! Entertainment latenight host Chelsea Handler has sealed a rich deal with E! parent Comcast Entertainment Group that keeps her at the cabler for at least the next three years.

Deal, said to be worth as much as eight figures, means Handler will continue as the host and exec producer of “Chelsea Lately” through 2012.

She’ll also produce series for Comcast’s stable of nets (which also includes G4, Style and the on-demand FearNet service) via her new shingle, Borderline Amazing Prods. Comcast Entertainment Group gets first-look rights on any projects that come out of Borderline Amazing through 2012.

Handler runs the shingle alongside “Chelsea Lately” head writer Tom Brunelle, who also will continue as exec producer of the gabber.

Handler is currently dating Comcast Entertainment Group prexy-CEO Ted Harbert; her deal was actually announced by Lisa Berger, E! exec VP of original programming and series development.

“Chelsea Lately” is a “breakout hit that has significantly grown E!’s latenight audience, particularly among young women,” Berger said.

The talkshow, which bowed in July 2007, last month moved up to the 11 p.m. slot, where the network immediately posted ratings gains. “Chelsea Lately” averages 746,000 viewers, up 31% over the slot’s average last year.

According to the cabler, Handler scores more women 18-34 viewers than “Jimmy Kimmel Live,” “Late Late Show With Craig Ferguson” and “Last Call With Carson Daly.”

Separately, Sony Pictures TV is currently adapting Handler’s book, “Are You There Vodka? It’s Me, Chelsea,” with Barry Sonnenfeld aboard to exec produce.

Both that book and “My Horizontal Life” have spent months on the New York Times bestsellers list.

Handler’s credits also include Oxygen’s “Girls Behaving Badly” and the online series “In the Motherhood” (although she doesn’t appear in the upcoming ABC TV version due to her E! commitments).

The Handler pact means two of E!’s biggest stars are now locked in for the next several years. Comcast sealed a deal with Ryan Seacrest last year that also keeps him at the company through 2012.