4. Kevin Bacon
These days Bacon is as well-known for his TV adverts as for his acting. His heyday was back in the '80s, when success in a string of blockbusters, including She's Having A Baby, The Big Picture and particularly Footloose, made him a household name. He has continued to act in a wide range of roles and productions, although he seems to have reduced his work rate over the last few years.
The role in Footloose was the only time where he seems to have been able to tap his musical side, but he's managed to scratch that particular itch by maintaining a parallel career with his brother, Michael, in The Bacon Brothers. As with many entries on this list he is equally adept as a singer and a guitarist, with a handful of albums in the country rock/Americana field behind him.
As with so many musical actors, it is an uphill task to convince the public at large to buy into the other side of their creative muse, which means that, unfortunately, only those who are already fans tend to know about the extra-curricular musical activities. Given Bacon's talents as a musician that is a particular shame, as he is a gifted songwriter whose work deserves to be heard by a much wider audience.