Christie Brinkley’s cheating ex-husband recorded a steamy x-rated romp with his then-teenage mistress Diana Bianchi, a new report claims. A sex tape allegedly featuring Brinkley’s ex Peter Cook and Diana Bianchi is presently being shopped to the highest bidder.

The New York Post writes: Yesterday, we were shown a series of stills from a video depicting Cook and Bianchi, both nude, having sexual intercourse on a brown love seat. They also show Bianchi performing a sizzling striptease down to a pair of black, G-string panties and then to her birthday suit as Cook holds his crotch.

Diana says she was “unaware that he was videotaping their sexual encounters.”