Sarah McLachlan has spent the last 35 years touching souls.

McLachlan released “Angel” in 1998 and it remains one of her most successful, impactful songs to date. Accomplishments aside, it is also one of her favourites. “Angel” has resonated in a meaningful way with not only fans but other artists.

Brandi Carlile watched McLachlan perform “Angel” at the breathtaking Gorge Amphitheatre in Washington 25-years-ago at a Lilith Fair show. Carlile watched from the top of the hill, picturing herself onstage with McLachlan. In a nearly unfathomable excercise in willing something into existence, Carlile performed a duet of “Angel” with McLachlan at the Gorge this past June.

“It was really, really beautiful,” McLachlan tells ET Canada ahead of her headlining slot at the Constellation Festival in Squamish, B.C. on July 24. “She championed me right before I got on stage to telling that story. It was three years. Every year she sat up there and watched us perform and she said we showed her that she could do exactly what she wanted to do. It’s a big part of the reason that she was headlining that show that night. It was an honour to sing with her. I’m a massive fan.

“She’s an incredible human being and has worked really hard to get to where she is today. She’s done it on her own terms and with a whole lot of integrity. So I have nothing but huge respect for her and it was so much fun to get to play to 18,000 people again. Her fans are unbelievably fantastic.”

Sharing “Angel” with others is a joy for McLachlan.

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“It’s my favourite song to sing and it’s my favourite song to sing with other people,” McLachlan says. “I’ve had the opportunity to have a lot of great voices lent to that song. Hers is is one of the finest. Just singing with her that night was it was really powerful.

“Watching her, looking at her singing and watching each other, it was such a mutual love and admiration and joy and release. That is the great thing about making music together: the energy that gets shared and the connection that happens. It’s really powerful.”

Darryl McDaniels, better known to hip-hop fans as DMC of Run-DMC, credits “Angel” for saving his life. It was a story he told McLachlan at a Clive Davis Grammys party.

“I met him for the first time and he basically was like, ‘This might be my only chance to tell you the story.’ So he just rapidfire told me this whole story,” McLachlan says. “I think that song, perhaps more than any of my songs, has been that one piece of music that has just resonated really powerfully with other people. They’ve been able to take it into their own lives and make it their own and have it help them in some small way.

“I’ve had so many people over the years tell me they played that for their at their mother’s funeral or was a song they played through a lot of heartbreak, a lot of loss, but was a healing thing. It was a piece of comfort that was able to be provided at a time when a really challenging time in people’s lives. That’s beautiful validation as an artist to hear that.”

That emotional connection to music is what McLachlan strives for with every release.

“I don’t think we ever do as artists whether something is going to stick and have real, lasting value,” McLachlan says. “I don’t want to release anything that doesn’t feel impactful for me. If it hasn’t moved me in some way and it continues to feed me in some way, I’m not going to release it.

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“So certainly my hope as an artist is when I do put material out, it is able to to give provide comfort or joy or release or whatever. All the beautiful things music gives to people.”

McLachlan closes out the Constellation Festival on Sunday, July 24. The Squamish music festival also features fellow Canadian acts including Lights and July Talk.

“Being able to sleep in my own bed at the end of the night and getting to perform outdoors with one of the most incredible backdrops in the world,” McLachlan says. “That’s always really fun.

“Squamish is an amazing town. It’s got great people and it’s a beautiful place to live. I’m there part time now. I love it. I love my new adopted town and I’m super excited to play there.”

Fans in attendance for McLachlan’s festival date may be treated to unreleased music.

“I’ve been slowly churning away,” McLachlan said. “I’ve got about 14 songs in various states of completion and I’m doing some live shows now. I’m starting to pepper them in here and there, which is really, really fun. I don’t have a release date, but it is coming at some point.