Olivia Newton-John is decluttering — and the hundreds of items marking milestones in her multifaceted career she will be putting on the auction block are going to help the fight against cancer.

The pick of the crop include the iconic black leather outfit she wore in  Grease, with the Beverly Hills auction house holding the event estimating the value of that item alone at $US200,000 ($289,481).

The 71-year-old singer and actor says she will donate a large portion of the proceeds to the cancer hospital she founded in Melbourne.

Newton-John was diagnosed with breast cancer in 1992, and last year the disease returned in the form of a tumour in her lower spine.

“I am not sad at all to let go of these things,” Newton-John said.

“It’s just things, and I try not to be attached to things. I will keep beautiful memories and photographs.”

Olivia Newton-John’s Grease outfit can be yours for a modest $200,000-or-so. Photo: Paramount

The British-Australian entertainer starred as Sandy in Grease.

She was the curly-haired blonde who fell in love with Danny, played by John Travolta in the lively 1978 musical.

Newton-John wore the skin-tight outfit in the final number.

“The jacket, of course, was a wonderful way of transitioning into this hot character,” Newton-John said.

In addition to the leather suit there will be an estimated 500 other items in the auction. But she’s not getting rid of all of her keepsakes.

“There are some jewellery pieces I want my daughter to have. Some clothing I really like and my Grammys,” she said.

Among Newton-John’s four Grammys was the 1974 record of the year for I Honestly Love You.

-with AAP