Karissa Shannon's break-up with
Sam Jones III wasn't based on a ruse after all -- because Karissa and her twin sister Kristina tell TMZ, they ARE moving back into the Playboy Mansion.

We broke the story this morning -- Karissa
pulled a bait-and-switch on the "
Smallville" actor yesterday, lying about moving back into the Mansion with her sister ... so Jones would help her pack before she dumped him.
But something changed in the last few hours -- because the twins just rolled up to the Mansion, telling us, they're moving back into
Hugh Hefner's palace after all.
The girls shacked up with Hef for the first time back in 2008 -- living with him as his "girlfriends" for over a year.
He's out on bail facing 20 years in prison -- but ex-"
Smallville" actor
Sam Jones still needs to work ... which is why an LA court granted him permission to party in Mexico this week with his Playmate GF.

Sources close to the actor tell TMZ, Sam was paid to appear at Dady'O Nightclub in Cancun Thursday night -- alongside his GF
Karissa Shannon and her twin sis Kristina -- and in Hollywood ... that counts as a real job.
But Sam couldn't just hop a plane and fly south of the border ... the guy is awaiting sentencing for
his massive drug trafficking case -- scheduled for June -- and technically isn't allowed to leave the country.
So he did what any other actor in his position would do -- he filed papers with the federal court in L.A. asking for a special dispensation ... on the grounds that he needed the money ... and the court actually GRANTED it.
FYI -- the photo above is from the actual event. Celebrity justice at its finest.
Kristina Shannon -- one of the Playboy twins who famously dated
Hugh Hefner earlier this year -- is trying her hand at a new career ... that doesn't involve posing naked.

Apparently Kristina thinks she can sing ... cause she's working on a collection of "club hits" due out in February. She says she plans on doing all the singing herself and plans on working with at least one "big surprise" guest.
Hopefully his name is Auto-Tune.
The
Heidi Montag sex tape saga has exposed a glaring hypocrisy in the world of celebrity sex tapes -- straight sex trumps beautiful, innocent, glorious girl-on-girl action.

Sources close to the Heidi sex tape deal tell TMZ ... Vivid Entertainment is only slightly interested in the rumored video with Montag and the Shannon Playmates. They are, we're told, way more interested in the Speidi videos.
We're told Vivid honcho
Steve Hirsch is very clear ... the money tape is the one featuring Heidi and
Spencer Pratt -- a tape he believes could surpass
Kim Kardashian's sex tape in sales.
To sum it up ... video of Spencer Pratt is somehow more appealing than video of naked Playboy Playmate twin sisters. What is this world coming to?!?!?!?
UPDATE: Kristina Shannon tells TMZ she is "100% positive" that she is not in any sort of sex tape with either her twin sister Karissa Shannon or Heidi Montag.
Kristina adds, "I'm saddened by the situation with Heidi and my sister."
Playboy Playmates and biological
twin sisters Karissa and
Kristina Shannon, 20, got a lot closer at the Playboy mansion this weekend ... and shared a tender open-mouth kiss with each other.
It's OK to love your sister ... but is it really OK to LOOOOOOOOVE your sister?