F Fay Wray - actress in original King Kong film (1933). Like many famous Americans involved in acting, music , etc, she was actually born in Canada, but her family moved to the USA when she was young. Had an iconic, and much parodied, starring role in the film (if you don't count the giant gorilla!)
M- Mark Little . Not a Hollywood star and not American , but seen by millions in Australia and Britain on tv when playing the character Joe Mangel in "Neighbours". I was never really a "Neighbours" fan, but he later turned his hand to stand-up comedy, and that's where I saw him live on stage and met him. He seemed like a decent bloke. Think he now lives in England, but I'm still counting him as an Aussie!
I was on a beach in Egypt some years ago when everyone started standing up and waving at a boat in the sea - well, naturally I stood up too and an Italian lady told me it was Omar Sharif on his way to a poker game - apparently he was on deck waving back but I couldn't see him!