Possible Clues:

• Singer who is part owner of Forbes magazine
• Rocker-activist
• Good for Caesar?
• Cher's ex
• He sang “I’ve Got You Under My Skin” with Frank Sinatra on “Duets”
• U2 co-founder and Nobel Peace Prize nominee
• Irishman who was a Time magazine Person of the Year in 2005
• Activist Chaz
• Irish activist/sunglasses-wearer
• Singer in a leading band