Smash Mouth singer Steve Harwell, most famous for the band's 1999 hit "All Star," died at his home in Boise, Idaho, on Monday (9/4). He was 56.

Robert Hayes, Smash Mouth's manager, confirmed the news online. He noted that Harwell was surrounded by family and friends and "passed peacefully and comfortably." The cause of death was acute liver failure.

Formed in 1994 in San Jose, California by Harwell, guitarist Greg Camp, bassist Paul De Lisle and drummer Kevin Coleman, Smash Mouth released its first single, "Walkin' on the Sun," on Interscope in 1997. Two years later, the band found international success with "All Star," which peaked at #4. Taken from their sophomore album, Astro Lounge, the undeniably catchy anthem found new life in 2001 when it was featured in the animated film Shrek. The soundtrack, which also included Smash Mouth's cover of the Monkees’ “I’m a Believer,” went double platinum, and the film won an Academy Award for Best Animated Feature. The track was certified triple platinum in May 2020.

After Smash Mouth's move to Universal in 2005, its popularity started to wane. The band's final album, Magic, arrived in 2012.

Over the last decade, Smash Mouth continued to tour, but Harwell retired in 2021 due to health issues. He'd been diagnosed with cardiomyopathy. Following his initial diagnosis, he suffered from “nonstop serious medical setbacks including heart failure as well as acute Wernicke encephalopathy.

"Ever since I was a kid, I dreamed of being a rock star performing in front of sold-out arenas and have been so fortunate to live out that dream," Harwell told his fans upon his reitrement. "To my bandmates, it’s been an honor performing with you all these years and I can’t think of anyone else I would have rather gone on this wild journey with.”

Smash Mouth still tours with vocalist Zach Goode, who joined the band last year. Harwell is survived by his fiancée, Annette Jones; a brother, Mark; and three sisters, Carla Crocker, Michelle Baroni and Julie Harwell.