Those headturning trousers, a ‘pink ladies’ jacket, plus many more items from the actor’s 55-year career are going under the hammer. So why-yi-yi-yi now?

When Sandy told Danny to “Tell me about it stud,” in skin-tight black trousers and a leather jacket in the 1978 film Grease, little did Olivia Newton-John realise her character’s costume would go on to fetch a combined estimate of $230,000 (£185,000) at auction more than 40 years later.

These items of cinema history, along with 200 more of the actor’s costumes and personal clothes will go under the hammer at Julien’s Auctions in LA in November, with 32 highlights now on display at the Museum of Style Icons in Ireland.

Needless to say, the black trousers will take centre stage and Newton-John hopes that they get the same head-turning reaction as they did during production. “The night before we filmed You’re the One that I Want, John [Travolta] was filming Stranded at the Drive-in and I had finished filming. I was trying on costumes, hair and makeup in the trailer [and] I don’t think anyone knew it was me at first as all the heads turned and I thought: ‘Wow! What have I been doing wrong all this time?’” she tells me on the phone from her California home.

Facebook Twitter Pinterest Sandy’s ‘pink ladies’ jacket given to Newton-John by the cast and crew of Grease (left), plus the trousers and leather jacket from You’re the One That I Want scene. Composite: Julien's Auctions

“The trousers and jacket are the most identifiable of pieces and what people remember when they think of Olivia Newton-John,” says Martin Nolan, the executive director of Julien’s Auctions, who is organising the exhibition.

Although her character Sandy was memorably called “too pure to be pink” by Rizzo (played by Stockard Channing), a customised version of the “pink ladies” jacket, which was given to Newton-John by the cast and crew, will also be up for grabs and is estimated to reach $4,000. “It was most likely [given to me] at an afterparty or when we wrapped a scene with the pink ladies,” she says, as “they wanted me to have one of the jackets and feel I was part of them”. It is a bond that has remained: she is still in touch with Didi Conn, who played Frenchie (they would rehearse in her trailer), as well as Barry Pearl who played Doody, Kelly Ward who was Putzie and Travolta.

Facebook Twitter Pinterest Olivia Newton-John as Sandy in Grease, with Putzie (Kelly Ward), Doody (Barry Pearl), Sonny (Michael Tucci) and John Travolta as Danny. Photograph: Ronald Grant

Other Grease items in the sale will be less well known. A pair of nondescript tan leather dance shoes with a small heel (estimated to fetch $2,000) turn out to be Newton-John’s rehearsal shoes for the Grease dance numbers (“[so that] I was used to the heel,” she says). Most rehearsals were for the dance in the gym as, she recalls, “that was probably the one with the most choreography to be worked out. And then they had to be changed [from rehearsals on the studio lot] when we got on set because cameras changed and the room was different … but I got to bop with John and do things I had never done before.”

The pink lace gown and matching stole that she wore to the LA premiere of Grease is expected to get $8,000. She still remembers the energy emanating from the crowd when she and Travolta stepped out of their car. “I remember thinking: ‘Wow! How do all these people even know about this film?’”

Facebook Twitter Pinterest The gown worn to the 1978 LA premiere of Grease is expected to make $8,000. Composite: Getty / Julien's Auctions

The auction is, more than anything, a celebration of Newton-John’s 55-year career. Born in the UK in 1948, she moved to Australia with her family when she was five. By the time she was 15, Newton-John was on TV in a girl band. But her career took off in the 1970s, when she came back to Britain with hits including Take Me Home, Country Roads. In 1974, she was Britain’s entrant to the Eurovision song contest with Long Live Love – and came fourth; the winners that year were a then unknown four-piece Swedish pop group called Abba. The album of the same name propelled Newton-John into the US, with I Honestly Love You becoming her first No 1 there and earning her two Grammys. She has since sold an estimated 100m records worldwide, a trajectory that is sartorially documented in the auction.

Facebook Twitter Pinterest Shorts and top worn by Newton-John to promote her album Physical in 1981. Photograph: Julien's Auctions

A pair of white and gold lamé shorts and matching top, which she wore to promote her Physical album in 1981, are up for $4,000 and a beaded blue chiffon minidress she wore for her first world tour, Totally Hot, in 1978 is estimated to reach $2,000.

There will be some personal items, too, including the wedding dresses from her marriages to Matt Lattanzi in 1984 and John Easterling in 2008, which she is philosophical about letting go of. “I wouldn’t wear them again,” she says. “These things are in pictures, so I have a wonderful memory of them and that’s what it’s about. They’ve been hanging in a closet [in a Los Angeles storage facility] so it’s much better if someone is enjoying them and that the money goes to benefit something that I care about.”

Much of the proceeds from the sale will go to the Olivia Newton-John Cancer Wellness & Research Centre in Melbourne, established in 2015. Set within the Austin Health hospital campus, the centre offers holistic and traditional treatments, as well as education, training and research, and has more than 200 ongoing clinical trials. Newton-John has been diagnosed with her third bout of breast cancer, which has spread to her lower back, and she is still recovering from last year’s cancer-induced fractured pelvis. The remainder of the funds she may donate elsewhere and a portion she will keep, as, she says: “It’s my career.”

It was panned on release – so why are we hopelessly devoted to Grease 40 years later? Read more

Some significant items are missing from the auction, thanks to Newton-John’s past generous donations to other peoples’ sales. “[That’s] how I lost my red shoes from the movie [also worn in You’re the One That I Want] years ago,” she says. Others have been preserved in her archive out of luck; for example, the pink ladies jacket she wore on tour until her publicist caught her throwing it across the stage and, aghast, stopped her. She has kept it at home ever since.

Newton-John is keeping certain items “that have personal meaning to me”, she says, citing jewellery and items from her late parents or sister – as well as her four Grammy awards, “because they are the height of my success and the most important one I can receive for singing and the music, so I can give them to my daughter.”

The auction is likely to break records, but Newton-John remains self-effacing – and eerily similar to her on-screen character of Sandy. She keeps her multiple awards, from Billboards to People’s Choice, in storage, as “it would be funny to have them all over the house”, and doesn’t watch herself on screen.

Yet she remains proud of a career that has seen her rock’n’roll with Travolta, jam with Stevie Wonder in an LA club, skit with Wonder Woman and tap dance with Gene Kelly in the 1980 musical fantasy Xanadu.

“It was incredible to dance with Gene Kelly and John Travolta in one lifetime … I did the original Dancing with the Stars!” she laughs. “I feel lucky.”