We think we've found an interesting and unexpected way to have her join the family

Frank Spotnitz The X-Files Executive Producer

Despite speculation from fans of both Xena and The X-Files, the details of the character Lawless is to play are being kept a closely-guarded secret.

'Thrilled'

"We're thrilled to have an opportunity to work with Lucy, whose work we've admired for a long time," the show's executive producer Frank Spotnitz was quoted as saying by Variety.

"We think we've found an interesting and unexpected way to have her join the family."

The move comes as The X-Files starts its ninth series with a very different cast to its original line up of David Duchovny (Mulder) and Gillian Anderson (Scully).

David Duchovny has reduced his appearances to concentrate on a movie career, with Terminator 2's Robert Patrick replacing him as cast regular.

Gillian Anderson has said in a recent interview with The Sunday Times that she will soon "quit The X-Files" to spend more time with her daughter.

She also said she was to join the growing ranks of American actresses to appear on the West End stage.

Gillian Anderson and David Duchovny have been in the show since 1993

Duchovny and Anderson became household names around the world when the X-Files launched in 1993.

The two stars played FBI agents ordered to investigate the paranormal with Duchovny playing the role of believer Fox Mulder and Anderson as the sceptic Dana Scully.

Xena: Warrior Princess, shot in New Zealand but produced by Studio USA, recently ended after five years in production and more than 100 episodes.

The sword and sorcery fantasy series, still airing on Channel 5, follows the fortunes of she-warrior Xena (Lawless) and has earned a cult following in the last half-decade.

The first episode of the new series of The X Files is to be transmitted in the United States on 4 November.