Bradley Cooper has urged his fans to become bone marrow donors.

The 'American Sniper' actor was touched by the plight of 24-year-old Anthony Michaels, who has beaten cancer three times since he was first diagnosed in 2011 and is now undergoing radiotherapy on a spine tumour after chemotherapy proved ineffective, though a bone marrow transplant is his best chance of survival.

Bradley - who was introduced to Anthony by Delete Blood Cancer DKMS - said: ''Anthony just has the gift of positivity and gratitude.

''He understands the importance of life that we tend to forget on a daily basis. But I have the feeling he was like that his whole life not just when he was plagued by this horrible disease.

''Anthony hasn't found someone who he's compatible with yet and it's such a simple test.

''I think when it's not personal and you can't relate to it, you tend to not take action. But I dare anybody to read Anthony's story and not care about him right away.''

The 40-year-old actor - whose dad died of cancer four years ago - admitted not helping Anthony wasn't an option for hi.

He added to People magazine: ''Anthony just has a genuine love of every moment that he's alive and I find that to be very compelling.

''And especially heartbreaking because he's afflicted with essentially a terminal disease.''

Meanwhile, Anthony was very impressed with the 'Hangover' star's ''selfless'' attitude.

He said: ''He was a real humble guy and he was very easy to talk to.

''I didn't think he was going to be as selfless as he was so it was a nice surprise to say the least.''