Surprise! Olivia Newton-John to Appear on Dancing With the Stars ' Grease Night

Grease is the word this week on Dancing With the Stars, which will feature a fan-favorite guest of honor!

Actress and singer Olivia Newton-John, who played the female lead, Sandy Olsson, in the hit 1978 musical film, will make her return to the show and appear on the themed episode on Monday, Oct. 18, a rep for the show told E! News exclusively.

"Olivia Newton-John will be making a surprise guest appearance on Monday's show, in support of the competing couples who will dance to the music from her iconic film role," the rep said.

ABC had announced last week that its upcoming Grease Night episode will feature fellow movie alum and crooner Frankie Avalon, 81, singing his character Teen Angel's show-stopper "Beauty School Dropout" live in the ballroom, with a guest appearance by co-star Didi Conn, 70, who played Frenchie in the film. The 11 celebrity and pro-dancer couples will perform routines inspired by Grease.

Olivia's upcoming appearance on the show comes four years after she began fighting cancer for the third time. Amid her battle, she has continued to make sporadic appearances in public and on TV.

Keeping Score of Dancing With the Stars Season 30

This past February, Olivia gave an update about her health, saying on her native Australia's Channel 7 program The Morning Show, "I'm just very, very happy that I'm here and doing well and focused on the [Olivia Newton-John] Foundation Fund," referring to her charity, which helps fund research on plant-based and other natural treatments for cancer.

Olivia has appeared on Dancing With the Stars before. The star guest-judged a season 21 episode in 2015, sitting on the panel next to longtime cast member Julianne Hough, who would go on to play Sandy in Grease: Live the following year.

Olivia took part in a couple of Grease reunions in recent years. In 2018, amid her recent cancer battle and before she made it public, Olivia reunited with Conn, fellow Grease co-stars John Travolta —who played the male lead and her love interest Danny Zuko, and Barry Pearl—who portrayed Doody, as well as the film's director, Randal Kleiser, at a 40th anniversary screening and celebration for the film in Beverly Hills, Calif.

In December 2019, three months before the start of the COVID-19 pandemic, Olivia and John reunited again at a Grease sing-along event in Florida, where they wore their characters' costumes for the first time since the movie wrapped.

While she did contemplate retiring, Olivia has also continued her singing career. In January, she and her 35-year-old daughter, Chloe Rose Lattanzi, released their first joint single, "Window in the Wall."

Dancing With the Stars airs Mondays at 8 p.m. on ABC.

Behind the scenes drama? What do I watch next? Click here to get all the TV scoop straight in your inbox.