Teen Mom star Farrah Abraham in Sex Tape Riddle

Just days after her DUI arrest on St. Patrick's Day, Teen Mom star Farrah Abraham is at the centre of sex tape scandal.

According to TMZ, an X-rated video of the troubled 21-year-old mother-of-one has been leaked and is being shopped around to big porn companies in Hollywood.

Vivid Entertainment president Steve Hirsch confirmed that he had seen the video which is on sale to the highest bidder.

Abraham allegedly appears in the 30-minute smutty tape with an unidentified male partner.

Although the reality star vehemently denies the existence of a sex tape, she is said to be threatening to take legal action against those in the possession of the alleged clip.

When recently questioned over the tape Abraham muttered: "'I don't... exist... anything about that."

She later added: "If I had my own personal stuff, that's my own personal thing. If there's someone being rude and trying to get at me, then my lawyer will take care of that."

The sex tape scandal follows a dramatic few months for the MTV star.

In January Abraham, who has had more than $20,000 worth of plastic surgery in recent years, was caught kissing girls wearing just sexy lingerie at the Halo Ultra Lounge in Omaha, Nebraska.

Earlier this month, she faced backlash from fans when she claimed she was adopting a baby boy, but later confirmed it was just an April Fools' Day prank.

Abraham could be hoping to follow in the footsteps of stars including Kim Kardashian and Paris Hilton who skyrocketed to fame after their videotaped rendezvous were leaked online.