Robert De Niro has said working with Al Pacino and Joe Pesci on Martin Scorsese’s new film was “what we always wanted”.

The Oscar-winning director’s reflective gangster elegy The Irishman reunites him with De Niro, Pesci and Harvey Keitel, and unites him with Pacino for the first time.

The ambitious film took more than 10 years to put together and uses state-of-the-art technology to de-age the actors for a story that spans 40 years, but De Niro, who plays the title character, the hit man Frank Sheeran, said he maintained his belief that it would eventually happen.

Arriving at the film’s premiere at the BFI London Film Festival, where it was the closing gala, he told the PA news agency: “I felt the book was great.

“We were doing another script and I said, ‘Let me read I Heard You Paint Houses for research because I heard it’s so good, the character, this guy’s experience’.

“I read it and I said, ‘Marty, you’ve got to read this book’, and that is how it started.”

He added: “Me, Al, Joe Pesci, it was what we always wanted and we got it.”

The Irishman International Premiere and Closing Gala – BFI London Film Festival 2019
Robert De Niro (Ian West/PA)

Reflecting on what the film says about the process of ageing, De Niro replied: “I guess people get mellower.”

Pacino, who plays union boss Jimmy Hoffa, said it was a group reading of the script about four years into the project that made him believe the film might be a reality.

He told PA: “When they got it together and they started putting it together early, I think it was about 10 years ago.

The Irishman International Premiere and Closing Gala – BFI London Film Festival 2019
Al Pacino (Ian West/PA)

“And once they started putting it together, you saw it evolving and it was well done, the script, the writing and Marty Scorsese together.

“You do know when you have a script that has got something.

“It’s Marty first and then it’s the script together and that started to happen and that took a while.

“We had a reading, three or four years into it, of the entire cast, with a lot of people there to take a look at it and that turned out to be a very fortunate thing that we did because it got the people together, galvanised it.”

Keitel, who previously worked with Scorsese on films such as Mean Streets and Taxi Driver, plays mobster Angelo Bruno and said he saw the film as an combination of Scorsese’s previous works.

The Irishman International Premiere and Closing Gala – BFI London Film Festival 2019
Harvey Keitel and Daphna Kastner (Ian West/PA)

He said: “I think it has all the ingredients of every one of his films, about politics, about joy, about separation, there are a lot of similar themes to a lot of things he’s done.”

Discussing how it addresses the passage of time, he added: “That theme is so prevalent in every day life for me, everybody I know, the young going on and getting older, I’m smiling because it’s joyful to me, everybody dies.”

Meanwhile, This Is England star Stephen Graham, who plays mobster Anthony Provenzano, said he was blown away to work with his heroes.

The Irishman International Premiere and Closing Gala – BFI London Film Festival 2019
Stephen Graham and Hannah Walters (Ian West/PA)

He said: “It was amazing, it was absolutely unbelievable, these are absolute icons and legends and the most beautiful thing about it was there was no egos at all, they just took me under their wing and Marty created a wonderful atmosphere for us just to play.”

He added: “I think it’s that genre, all the other films he’s done, it’s an amalgamation of, and just beautiful storytelling and the fact that is spans over four decades or something like that and it was a joy to do.”