Kevin Costner has sent a special thank you message to British troops, praising them for their bravery on the frontline.

The movie star, recorded a message for the British Forces Broadcasting Service (Bfbs) whilst filming new movie Criminal, in Hampshire, England.

He pays tribute to the soldiers for "standing up for those who cannot stand up for themselves" and insists the U.K.'s armed forces are "America's strongest ally".

In the emotional clip, Costner says, "It's an incredible selfless thing you've chosen to do to be in the military. To volunteer when you could be pursuing so many other things with your young lives but instead choosing to serve your beloved country...

"In my career, I have been able to play characters that are smarter and braver than I could ever be. I have been able to play characters in the military who are heroic and paid the ultimate sacrifice. But the truth is, I have never served. And I have never been tested as you have. I have never made that same commitment. You are the real deal. The ones that will be called first in a crisis. It is important to me that you know that I know the difference between your lives and mine."