TMZ has learned Spencer Pratt is currently shopping what he claims is a sex tape featuring himself and his soon-to-be ex-wife Heidi Montag.

We're told Spencer has contacted the Rolls-Royce of porn -- Vivid Entertainment -- and is asking for a meeting.

As we first reported, Heidi has threatened to sue Spencer over a tell-all book -- but she has not made any mention of a sex tape. Unclear if the alleged sex tape with Heidi is pre or post-op.

Vivid honcho Steven Hirsch tells us, "I just got off the phone with Spencer Pratt about a sex tape with Heidi Montag."

He continues, "We are in early negotiations to possibly come to terms for a deal."

Spencer has told a friend that the alleged tape "makes Kim Kardashian look like an amateur."

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Heidi/Spencer Divorce -- The Clock is Ticking

Eva Mendes -- I'm Releasing the Sex Tape

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