Legendary singer Joe Cocker has died, the BBC reports. He was 70.

Cocker died of an "undisclosed illness," his agent, Barrie Marshall, told the news organization. According to ITV News, Cocker had been battling lung cancer.

He was "simply unique" and "it will be impossible to fill the space he leaves in our hearts," Marshall said.

Stars we lost this year

Born in Sheffield, England, Cocker got his musical start in 1961 with his band Vance Arnold and the Avengers. After playing for pubs, they got their first break in 1963 when they booked a gig with the Rolling Stones. Soon after, Cocker went off as a solo act and eventually found success after recording a gravel-voiced cover of the Beatles' "With a Little Help from My Friends," which many years later would be used as the opening theme for The Wonder Years. The single reached No. 1 on the British Top 10 charts in 1968. It later went gold after its U.S. release.

Over the next 40 years, Cocker went on to record hits like the Grammy-winning "You Are So Beautiful" and "Up Where We Belong," a duet with Jennifer Warnes. Other hits include "Feelin' Alright" and "Unchain My Heart." He toured all over the world and performed at both the original Woodstock and Woodstock '94.

Cocker was knighted by Queen Elizabeth in 2007.

He is survived by his wife of 27 years, Pam Baker.

In Memoriam: Remember the stars we lost in 2014