Mark Sheehan, the lead guitarist for Irish rock group The Script, has died at 46 following a “brief illness.” The band mourned Sheahan’s passing on social media, writing in a statement, “Much loved husband, father, brother, bandmate and friend Mark Sheehan passed away today in hospital after a brief illness” and asking that fans “respect [his family and bandmates’] privacy at this tragic time.” Sheehan, who was one of The Script’s founders in 2001 and had been best friends with frontman Danny O’Donoghue since age 12, sat out the U.S. leg of the band’s most recent tour, with O’Donoghue saying that he was choosing to spend the time with family. The Script’s self-titled first album debuted at No. 1 on the U.K. charts, and the group went on to put out more No. 1 albums and singles in the U.K. than any other Irish band over the following decade.