A professsional mistress alleged to have had an affair with Gordon Ramsay has made a surprise appearance on the season finale of Hell's Kitchen.

Wife: Ramsay with Tana

Sarah Symonds appeared for only a few seconds on the US version of the celebrity chef's TV show before the camera cut away.

Surprise: Sarah Symonds and Gordon, inset, on the show

With a blonde crop, and wearing a leopard-print top, she was seen with a near-empty plate on the reality show's Los Angeles set.

The programme aired in America last night, but was filmed in January 2008 - right at the time they were alleged to be romantically involved.

Ms Symonds, then 38, dined alone and dutifully filled out cards giving feedback to the wannabe chefs.

She finished her notes and said, "OK" before the camera cut to another scene.

Her appearance is likely to concern Ramsay's PR team and his wife, Tana. It is claimed Ms Symonds and Ramsay, 42, had a seven-year affair, which the fatherof-four denies.

They were pictured in a Sunday newspaper separately, leaving a Grosvenor Square hotel after a 75-minute meeting.

Ms Symonds, a PR and marketing executive from Newport in Wales, has made a career from sleeping with other people ' s husbands.

In 2001, she had an affair with disgraced ex- Tory minister Lord Archer.

Last year, she wrote Having An Affair? A Handbook For The Other Woman.

In the first edition, she told of a "friend" who had an affair with a "world-famous TV chef, well-known... for both his bad language and his good food".

She wrote: "He complained to my friend that things weren't going well between him and his wife and that he was made to sleep in the basement."

A spokeswoman for Ramsay declined to comment.