The Hollywood star steps behind the camera for his latest project, The Boys In The Boat, a sports movie about an underdog rowing team, thrust into the spotlight of Hitler's Olympics as they compete for gold.

Explaining his drive to direct, Clooney told Sky News: "It's more fun, you have a lot more control. I get to boss [the actors] around and I don't have to learn how to row. I still like acting. I have fun."

He then namedrops, as only an A-lister like Clooney can, "I've just done a film with Brad [Pitt]. He's an up and coming actor…"

Starting out as a TV extra in 1978, before going on to semi-regular appearances in sitcom Roseanne and a lead part in the humorously titled Return Of The Killer Tomatoes, his breakout role came in medical drama ER.

For many he will always be Doctor Doug Ross, a role he played from 1994 to 1999.

He's since gone on to win a plethora of awards - including two Oscars - starring in numerous films as well as successfully segueing into producing and directing.

That's aside from his political and economic activism, and home life as a father of two alongside his wife, human rights lawyer Amal Clooney.

So, what is it about directing that floats his boat?

Clooney explains: "Directing is a fun thing to do. It's fun to come in in the morning and it's fun to write a screenplay and then have somebody build a set that you wrote, it really is.

'You can't just do one thing'

"As you get older, you need to have other things to do. You can't just do one thing. I'm lucky because I'm 62 and I get to do the stuff I love, and a lot of people don't get that.

"I'm well aware of it, and I celebrate it because, you know, if I'm not having fun, I think people would be really p*****d off.

"You know, if they look at my life, you go, 'If you're not enjoying that, then, you know, then who knows..."

For this latest film, Clooney was tasked with wrangling eight young actors who'd never held an oar before and transforming them into convincing Olympic rowers.

Training consisted of rowing four hours per day, before working out for an extra hour several months before filming began, plus training during the shoot, after wrapping each day.

And Clooney had a rule about who would make it into his cast and crew.

"I only want to work with people that want to be there and like what they do because these are long hours, they are hard. It's hard to do.

"You know, no one's here to complain. We're not complaining. But they are long hours and it's a lot of work. And so, people have to enjoy what they do, because I really don't want to be around people that don't want to come out of their trailer.

"I'm from Kentucky. We try to stay out of doors."

'Short shorts' nostalgia

British actor Callum Turner, who plays real-life rower Joe Rantz in the movie, tells Sky News working with the superstar director was "a wonderful experience".

He is sitting next to Clooney at the time, but you get the feeling he really means it.

The 33-year-old credits Clooney with "providing a space for everyone else to have fun".

And he's not joking. It turns out Clooney - who Turner describes as "an amazing basketball player" - installed a hoop on set to wind down while not filming, or rowing.

And while Clooney didn't partake in the rowing itself (he says he didn't want to give the cast "ammunition" to make fun of him) he did give the shorts a go.

He jokes nostalgically: "I always wear the shorts. I like them. By the way, when I was growing up, we wore shorts like that. It wasn't even short shorts, they were just called shorts."

'Gorgeous George'

Joel Edgerton, who plays Coach Ulbrickson in the film, dubs Clooney "gorgeous George," adding, "he's a beautiful man".

The Australian star says he looks up to Clooney as both an actor and director.

"It was interesting because he's directed movies that he's not front and centre of or not in at all. And this is obviously one of those.

"I always wondered, with the big career that he has, why does he do that? Because he could always just take the money, the bags of gold, and walk away as an actor."

Edgerton puts it down to Clooney really caring about stories, sports stories in particular.

He goes on: "He really had done his research. And he's very efficient, he knows what he wants on a kind of craft level.

"And he's got volumes of stories… And then you realise, 'Oh, I might be in one of these stories one day - I'd better be a good guy'.

"He's fun to listen to all day long."

The Boys In The Boat is in cinemas now.