Canadian folk singer Kate McGarrigle, mother of musicians Rufus and Martha Wainwright, died on Monday. She was at 63.

McGarriagle enjoyed a long, successful musical partnership with her sister Anna and the duo recorded more than 10 albums together in the ’60s and ’70s, Spinner.com reports. Kate had been suffering from clear cell sarcoma, a rare form of cancer.

“Sadly our sweet Kate had to leave us last night. She departed in a haze of song and love surrounded by family and good friends. She is irreplaceable and we are broken-hearted. Till we meet again dear sister,” Anna McGarrigle wrote on the sisters’ website www.mcgarrigles.com Tuesday.