The pop-rock star and the Nickelback frontman collaborated on her new album Head Above Water

Products in this story are independently selected and featured editorially. If you make a purchase using these links we may earn commission.

There’s nothing “Complicated” about Avril Lavigne‘s relationship with ex-husband Chad Kroeger.

In this week’s issue of PEOPLE, the pop-rock star tells PEOPLE, “Chad and I are super close.”

Indeed, Lavigne, 34, collaborated with the Nickelback frontman, 44, on her new album Head Above Water, with Kroeger helping cowrite the empowerment anthem “Warrior.” The song — like many on Lavigne’s new record — is inspired by her debilitating battle with Lyme disease.

“I’m really grateful to have had someone like him in my life who cared while I was getting back up on my feet,” Lavigne says of working with her ex amid her health crisis.

Lavigne and Kroeger split in 2015 after two years, but there are no hard feelings between the pair.

2013 Billboard Music Awards - Arrivals
Chad Kroeger and Avril Lavigne (in 2013)
| Credit: Kevin Mazur/WireImage

“He took me under his wing, he got me in the studio, he recorded me, he was very encouraging. He helped me with some of the songs that I wrote, because he’s such a good songwriter — I’d be stuck on a lyric or stuck on a part, and he’d help me finish a song if I couldn’t and he would record it,” Lavigne says.

“He’s just always been a cheerleader of mine and always been such a huge fan. He’s in my corner, he’s on my side, and he’s always been really great,” she adds.

This isn’t the first time Lavigne has stayed friendly with an ex following a divorce. She and her first husband, Sum 41 rocker Deryck Whibley, split in 2009 after three years together. But they went on to team up for her 2011 album Goodbye Lullaby, on which Whibley is credited as a producer and engineer.

Avril Lavigne at home in L.A (Feb. 5, 2019)
| Credit: Cliff Watts

Lavigne began writing songs for Head Above Water, her sixth album and first since 2013, during her devastating battle with Lyme disease. The singer says she was bedridden for two years as she treated the disease with antibiotics and herbs. And she leaned on family, her faith and songwriting in her darkest moments.

“Music really lifted me up and made me feel better,” she says. “At first I didn’t know I was making an album — I just naturally turned to songwriting in a time of healing.”

Today, Lavigne — who has been linked to Phillip Sarofim since last April — is still managing her disease but is happy and healthier.

“I’m in a good place,” she says. “It’s important to live your life to the fullest every day.”

Lavigne’s sixth album, Head Above Water, will be released Friday. For more on Lavigne’s life now, pick up the latest issue of PEOPLE, on newsstands Friday.