Hollywood star John Travolta wowed guests at a charity ball when he performed an impromptu Grease-style dance with his wife.

The usually private actor, famed for his dancing roles in movies such as Saturday Night Fever, leapt from his seat at the event in East Grinstead and joined soul singer Isaac Hayes on stage.

Thousands who packed into a marquee at the UK base of the Church of Scientology hoping to catch a glimpse of the Pulp Fiction star danced along in disbelief.

Travolta and his wife Kelly Preston took centre stage on a raised podium to dance to the soul classic Stand By Me.

Other performers flown in for the fund-raising event at the church's castle, including Broadway singer James Barber, musician Mark Isham and female vocalist Elena Roggero, returned to the stage for the finale.

Organisers of the International Association of Scientologists said Travolta, who pilots his own jetliners, had flown in especially for Sunday's gala ball and was expected to leave yesterday.

During the concert, cheques were presented to UK charities the Royal Commonwealth Society, Age Concern and City of London Police charity City Kids, which helps inner-city children and those affected by the July 7 bombings.

Travolta and his wife then went on stage with the concert host, Patriot Games actress Anne Archer, to present a £40,000 cheque to Harry Lee, Sheriff of New Orleans.

The Face Off star and Ms Preston joined Scientology ministers to help the police in the US city in the aftermath of Hurricane Katrina.

Travolta said: "The police officers and their relatives working in New Orleans at that time suffered the same losses as everyone else."

Sheriff Lee said to the concert audience: "After Katrina, I was up to my elbows in alligators and looked up and there was John and Kelly.

"Not eight weeks later, here I am 10,000 miles away in a room full of the most committed people I have ever met and there's John and Kelly again."

Travolta, who received a standing ovation as he walked into the marquee, is a firm supporter of the Church of Scientology along with fellow Hollywood legend Tom Cruise.