Olivia Newton-John 'Feeling Great' 3 Years After Cancer Diagnosis — and Looking Forward to Daughter's Wedding

Olivia Newton-John Is ‘Feeling Great’ 3 Years After Cancer Diagnosis — and Looking Forward To Daughter Chloe's Wedding

The mother-daughter duo also talk about their new single together.

Olivia Newton-John has a lot to look forward to in 2021.

Not only is the beloved Grease star, 72, planning to release a new duets album, but she'll also get to watch her daughter, Chloe Lattanzi, walk down the aisle with her fiancé of 10 years, James Driskill, in a "small wedding" later this year.

"I'm so lucky to still be doing all these things," Newton-John tells PEOPLE. "I don't think I imagined living this long! I feel very blessed."

After all, the past few years have been difficult ones for Newton-John, who was diagnosed with stage 4 metastatic breast cancer in 2017. But she says she's "feeling great" — so much so that she and her husband John Easterling launched their Olivia Newton-John Foundation Fund recently in order to continue to support research into plant medicine for cancer.

"I'm very lucky to be married to a wonderful man who is a plant medicine man, and he has great knowledge," she says. "Now he's growing medicinal cannabis for me, and it just has been wonderful. It helps me in every area."

RELATED: Olivia Newton-John and Daughter Chloe Release New Duet Together Called 'The Window in the Wall'

What has also helped Newton-John through her cancer journey has been having her daughter (from her marriage to ex-husband Matt Lattanzi) there by her side. Though they've always shared a tight bond, the mother-daughter duo have gotten even closer as they've quarantined together in California during the coronavirus pandemic.

"I worked my whole life, and the longest period I can remember being home was my pregnancy with Chloe and the first year or two of her life," says Newton-John. "So it's been wonderful reconnecting with my baby. She is my reason to be."

Michelle Day Chloe Lattanzi and Olivia Newton-John

On Jan. 22, Newton-John and Lattanzi, 35, released their new duet, "Window in the Wall," which will be included on the star's upcoming duets album. The song first came to Newton-John by email, from a woman she had met years ago.

"Out of the blue, she sent me an email saying, 'I found this song, and I think you need to sing it,'" she explains, adding that she felt an instant tinge of dread. "I thought, 'Oh gosh, I know it's not going to be good. How am I going to tell her?'"

RELATED: Olivia Newton-John Shares Health Update on Breast Cancer Diagnosis: 'I'm Winning Over It Well'

But when she listened to the song for the first time, she was on board.

"It moved me to tears," she says. "It's a very healing song. I thought, 'This is very special, and I want to sing it with Chloe.'"

When Newton-John asked Lattanzi to join her on the track, she responded, "Yes — no questions asked."

"I was flattered and honored," says Lattanzi. "She could have asked anyone, and she asked me. That meant the world to me. It's my dream job — I get to spend time with my favorite person."

Ever since Lattanzi was a little girl, Newton-John says she knew she would follow in her musical footsteps.

"She would sing and perform and knew the words to everything on the radio and every record," she says. "And then she went through a shy period and didn't want to do it as much. When she was about 13, we made a TV movie together and she sang 'At Last,' which is a classic Etta James song. It was so moving, and I went, 'Oh boy, she has it.'"

Lattanzi has since released her 2016 studio album, No Pain, which included a reworking of her mom's 1980 hit "Magic" from the film Xanadu.

"As a kid, I wasn't paying attention to her as a celebrity," Lattanzi says. "She's my mom, you know? Like, she takes me to school. I think as I've gotten older, that's when I got to listening to her music. I did a re-imagining of 'Magic' because I loved it so much."

Olivia Newton-John and Daughter Chloe Lattanzi

Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday. Get a taste of the podcast below.

In addition to the music, Lattanzi has also gotten to borrow some of her mom's style.

"When I was in my early teens, she had a closet full of costumes from her movies," she says. "I think one time she came home, and I was trying on the boots from Xanadu, like the big thigh-high cowboy boots. I wore them for Halloween, I believe."

Adds Newton-John: "I know what you had! You wore the Xanadu the tank top, and you didn't realize it was special. She put it in the washing machine."

As she prepares to walk down the aisle, Lattanzi is keeping in mind a sage piece of advice her mom once gave her: "Don't change for anybody because that's not love."

"She picked a good one," Newton-John says. "So I haven't had to say much!"