It may be an easier question to name some top stars who haven't crossed over.
As some of the posts suggest it's been happening for decades from the rat pack & elvis in the 50s to the soap stars in the 80s, rappers in the 90s and now any young attractive actress.
It seems that these days if you are a rapper you will get a part in a movie. The same with RnB. Beyonce, Lauryn Hill, Queen Latifa, Fergie... the list goes on and on.
Some of the top hollywood stars may do it as a "relaxation" thing away from the movies like Russle Crowe or Woody Allen.
and then you get the young actresses like Love-Hewitt (ok last century

), Johannsen, Panettiere.
These types of artists seem to do well in Japan. I'm not sure what it is with them. Maybe they are obsessed with celebrity and don't care how it sounRAB or maybe they just like the novely value.
It does seem if you get to the top in either profession then you will get the call to do the other.
and how could you forget Bruce Willis
