Bradley Cooper tells Steve Pratt how he discovered a bloodlust for success as he took on the leading role in his latest movie.

WHAT was in the blood, Bradley?

That red stuff you start licking and sucking off the floor in your new film Limitless? It looks disgusting. “Something sweet,” says Hollywood actor Bradley Cooper.

“Maybe it reveals my state of mind, but it was the reason – probably – I wanted to do the movie. When I came across that scene in the script, I thought I’d love to see that in the film and I’d love to be the one that does it.”

So there he is lying on the floor slurping on the blood draining from a newly-deceased corpse. “Thematically, it’s the moment you realise just where this character is. If the movie works or doesn’t work, you’ll be able to tell in that moment because if the theatre is laughing at the actor pretending to drink the blood, we’ve completely failed.

“But if you’re with Eddie at that moment and you’re watching a guy at his lowest, what he will do to survive, the idea of drinking blood and whatever that creates in you as a reaction, we’ve succeeded until that point.”

Blood or not, there must have been some added pressure doing the movie in which you’re the leading man and not just one of the ensemble.

“I would have felt tremendous pressure if I’d shown up at work without doing the preparation.

I’d probably have had a panic attack and been put in hospital because there wasn’t much time. We shot in 38 days and the narrative is completely dependent on Eddie Morra.

“Making a movie is like running a race, a marathon. In The Hangover and The A-Team, we’re runnng. But this, I’m by myself running the race. It’s also an opportunity to really bond with your director. You and the director in the trenches together, which I love and can’t get enough of.”

Even working opposite Robert De Niro wasn’t scary “because my connection with, my relationship with De Niro pre-dates the movie, at least in my mind,” he says.

“The first movie of his I saw was Raging Bull. Before I met him I thought his hands were just like my grandfather’s. I didn’t know he was Irish Italian, I’m Irish Italian. He reminded me so much of my family.

“I always felt a real emotional connection to his work. He was one of the first actors who made me cry when I watched. He spoke at our school and I asked him a question in 1998.

“Then I put myself on tape to play his son in a movie. He saw the tape and then I had a chance to meet him in his hotel room and we spoke for about 15 minutes. Then I was a juror at the Tribecca film festival, so I saw him around.

“I had this big lunch with him, I said ‘hi Mr De Niro’. We met last year for Everybody’s Fine. But he had no idea who the hell I am.

“The story continues a year later. I am in his hotel pitching him an idea to play a character in a movie. It’s a very odd, odd turn of events.”

In the event, acting opposite De Niro was “the most effortless experience” he’s had on an acting level. “He’s a wonderful human being, very generous. He’s been doing this for 40 years and his level of excitment and willingness to work on the day in the scene is unparalleled.”

Limitless sees Cooper as an aspiring writer whose life is transformed by a pill that allows him to use his brain to 100 per cent of its potential.

Among the by-products are learning to speak a language in a day – leaving Cooper to have conversations in Chinese, Russian, French and Italian.

“That was really fun,” he says. “To pull it off you can’t just speak it, you have to handle it and show you can talk all day. Each language brings a certain physicality. The Mandarin is staccato and Italian is langorous, so I loved doing that. I had a freebie with French because I speak French.”

What he doesn’t have is a pill that will make Limitless a big hit and consolidate his status as a Hollywood leading man. In the past, he’s tended to be part of ensemble casts.

“There are moments in life where there are consequences to whether something is succesful.

I remember when I did this play on Broadway, I thought if this doesn’t go well, it actually is going to make a difference.

“I was brought up do my best. But there are going to be ramifications. Unfortunately, if it doesn’t do well or isn’t well received, it may be tougher for me to have a studio or someone funding the movie to say, ‘You know what, we can rest the main character on this actor’s shoulders. I feel he can be compelling enough for viewers to watch for two-plus hours’.”

One big dilemma with Limitless was how to portray a man under the influence of a drug that doesn’t exist. He was, to a certain extent, working in the dark.

He didn’t get Eddie’s drug-induced moods right the first time. “The week we started shooting, I was doing him a little like a cyborg.

There was a mechanical aspect to it and I remember watching playback with the director and I thought, am I on the drug? I’m bored. So we got rid of that very early on.”

Cooper is pleased when we start discussing what to call Limitless, how to categorise it as a comedy, a thriller or what have you.

“In movies today it seems as if there’s a generic code where you can cypher through your four categories and the prevailing one is remake. I’m about to be part of The Hangover 2 and I just did The A Team, but this is an interesting concept.

“There aren’t movies like this – what would you do if you could unlock your full potential and you could be the best version of yourself?”

Which brings us back to Cooper’s status on the Hollywood ladder of fame. He accepts that The Hangover success provided the opportunity for him to get involved in Limitless. Now he’s moved up to the next level. “It’s hard to say if it was a vertical shift, but it was a shift. Certainly it was vertical financially. With Hangover 2, I never thought I’d get paid that much money in my whole life. That was insane, for sure.

“But it’s also tricky. There’s a scenario where this movie doesn’t do well, but Hangover 2 is a huge success and you can make buddy comedies the rest of your career.”

􀁧 Limitless (15) is now showing in cinemas.