Ashton Kutcher is keen to dedicate his new movie to the lifeguards who helped save lives after Hurricane Katrina because playing one of them made him realise what they mean to America.

The actor plays an ambitious rookie learning the ropes from veteran Kevin Costner in The Guardian and admits he came away from the film with a new respect for all lifeguards.

He says, "They're a special group of guys. I didn't even know that the Coast Guard had an elite unit. The only thing I'd ever seen was at the end of the film Perfect Storm when you see these guys jumping out of the helicopters.

"For me, it was incredible to meet someone who is that tough but has that big of a heart. These guys are real big tough guys and they're so compassionate.

"I'd asked them about their saves and things that they've done and you can tell that they care about perfect strangers and that's a special kind of human being. This movie is a thank you to the Coast Guard for saving so many lives during Hurricane Katrina. They all work so tirelessly with so little credit."