Karissa Shannon -- The Sex Tape Deal Is Done

TMZ has learned ... former Playboy Playmate Karissa Shannon and her BF, "Smallville" actor Sam Jones, have finally agreed to release their sex tape ... and all it took was cold, hard cash -- that's what she said.

Sources close to the couple tell us they both agreed to a deal with Vivid Entertainment when the offer hit the "six-figure range."

Steven Hirsch -- the president of Vivid -- tells us, "We are excited to finally distribute this amazing DVD. Not only is it extremely kinky for a celeb sex tape, Karissa is absolutely beautiful. And as for Sam, let's just say he's no 'Smallville.' This is sure to be one of our all-time best sellers."

Watch your backs, Paris and Kim K -- sounds like you've got a challenger for the title.

On Saturday, Karissa's boyfriend Sam Jones III was spotted entering MyStudio where he told X17 that the meeting with Vivid Entertainment chairman, Steven Hirsch "went good." He said that Karissa was "outta town getting money," and when asked about Karissa's twin, Kristina saying that the sex tape doesn't even exist, Jones just said, "whatever!"

Credit: TMZ / X17 Online