British pop sensation Robbie Williams said Wednesday that he offered to donate his bone marrow to save the life of a fan who needs a transplant because she has leukemia, reports Reuters. Williams said that he was so moved by 23-year-old Johanna MacVicar's heartbreaking situation that he signed up as a donor as soon as he heard that a transplant might save her. "I can't believe how easy it is to join the register ... if I can help save somebody's life that easily, then count me in," Williams said in a statement issued by his record company, EMI. "Robbie is a remarkably down-to-earth guy with a heart of gold, and I will be eternally grateful," MacVicar said, according to Reuters.