Comedian Dane Cook's live-in girlfriend is denying published reports that her funny man is having a fling with divorcee Jessica Simpson.

Valli Girls lead singer Raquel Houghton tells Friday's Boston Herald reports of her boyfriend cozying up to his co-star in the film "Employee of the Month" are "obviously all lies."

Cook's brother, Darryl, admitted his brother lives in Los Angeles with Houghton but played the Simpson angle coyly, responding with, "We have no comment at this time," the Herald said.

The Herald goes on to quote sources saying Cook and Simpson are "just friends" and have more of a brother-sister relationship than anything else.