Academy Award winning actor Robert De Niro says that he and 'Righteous Kill' co-star Al Pacino weren't always friends.

Speaking at the UK premiere of the new film, De Niro commented on the long-standing relationship between he and fellow influential actor Pacino throughout the years, saying: "There’s no rivalry now but there was when we were younger. My rivalry is with Dustin Hoffman and Brad Pitt."

'Righteous Kill' was directed by Jon Avnet — whose other director credits include 'Friend Green Tomatoes', 'The War' and 'Up Close & Personal' — and it tells the story of two veteran New York detectives who start suspecting that they might have locked away the wrong person in a murder case they investigated years ago, when they notice a connection between a past case and a recent murder.

The film was premiered in London’s Leicester Square last night, and also stars recently re-united New Kids On The Block band member Donnie Wahlberg and Curtis Jackson, a.k.a rapper 50 Cent.