David Bowie, the legendary rock star who died last week of cancer at the age of 69, managed to keep the exact nature of his illness a secret from all but a few people close to him, The Independent reports. However, a friend of his claims Bowie had liver cancer.

Last week, Belgian theater director Ivo van Hove, who worked with Bowie on Lazarus, a new stage musical based on his music, told the website dutchnews.nl that the star revealed to him that he had liver cancer a little over a year ago as an explanation for why he was not able to attend rehearsals for the show. Bowie’s producer, Tony Visconti, also recently suggested that the artist knew for a year that his cancer was incurable, calling his last album Blackstar a “parting gift.”

Rumors of Bowie’s health had been circulating since at least 2004, when the star collapsed after coming off stage in Germany, where he was later taken to a hospital and underwent emergency heart surgery.

Many have pointed to Bowie’s long-time smoking habit and heavy drug use, which he sang about extensively in the album Cracked Actor, as other potential reasons for his passing.