(CNN) -- The frontman of rock band Sum 41 was hospitalized after being attacked in a bar in Japan this week, according to postings on the band's website.
Singer Deryck Whibley suffered a slipped disc in his back after he was attacked by three people Thursday while in Japan for the Summer Sonic music festival, the band said on its official web and Twitter pages.
Japanese police are investigating the incident, said the band, best known for its hit "Fat Lip."
Despite the injury -- and against doctors' advice -- Whibley planned to perform as scheduled in Tokyo on Sunday.
Whibley, 30, originally from Ontario, was married to fellow Canadian rocker Avril Lavigne for three years. The couple divorced in 2009.