Former Beatle George Harrison became very excited about the ukulele, especially in the last few years of his life. He was reported to have always travelled with two ukuleles so that he could play with someone, including producer and musician Jeff Lynne and fellow former Beatle Paul McCartney.
Eric Clapton plays the ukulele on the Bonzo Dog Band's "The Intro and the Outro".
Although not as widely-known, Keith Green was playing the ukulele when he was 3 years of age.
Violinist Sara Watkins, known as a member of Nickel Creek, is a ukulele player. She only plays it occasionally, like on the song Anthony.
Multi-instrumentalist and producer Jon Brion sometimes performs a version of Phil Lynott's "The Boys Are Back In Town" live solo on a ukulele
http://en.wikipedia.org/wiki/Ukulele