SYDNEY: John Travolta and his “Grease” on-screen love Olivia Newton-John have recorded together for the first time in 30 years, making a Christmas album honouring the US star's late son Jett.

Speaking to Australia's Fairfax Media via telephone on Tuesday, the pair said they had remained close friends since their roles as Danny and Sandy in the musical hit and were delighted to be working together again.

“Olivia and I have always wanted to work together again... but unless it's right and organic, it feels like you're forcing something and I didn't want anyone to feel that way,” Travolta said on why it took so long.

The star of “Pulp Fiction”, “Get Shorty” and “Hairspray” said an album was appealing because “I love to sing and I don't get a chance to do it a lot”.

“To join Olivia again, where we've succeeded at this level, to do that is a beautiful opportunity. I can't believe it,” he added.

Their new album, “This Christmas”, includes a song by John Farrar, who wrote their famous pop duet “You're the One That I Want”. The video for the new song will have its global release on Wednesday.

Cancer survivor Newton-John, who admits she still has the skin-tight black pants she wore in the movie, said she was still surprised at the success of the film about the love affairs of 1950s high school students.

“We still have little kids coming up to us who are discovering the movies.

It's like three generations who love the movie, who are going to be thrilled to see Danny and Sandy, as they think of us, together again,” the Australian said.

Proceeds from the album, which also features Barbra Streisand, Tony Bennett and James Taylor as guest artists, will go towards the Jett Travolta Foundation and the Olivia Newton-John Cancer and Wellness Centre in Melbourne.

“For us, it's a wonderful way of giving back to causes that we care about and we're also giving the fans back something that they might like to see us do,” Newton-John said.

“Hopefully they'll like it as much as we hope they will.” Jett Travolta died in 2009 aged 16 after suffering a seizure and his father said Christmas can be a difficult time for his family.

“Doing something for him makes it easier, because you're doing something, you're proactive, you're raising money for the foundation that represents him,” the actor said.

“It felt effortless. And everybody hopped on board effortlessly. We called Barbra and Tony and James and they all knew my son, so they just wanted to do this from their heart.”