Charles takes Camilla to meet his pal Pacino

It seems an unusual friendship: the star of Hollywood's Godfather trilogy and the Prince of Wales.

Yet when Al Pacino was introduced to Charles seven years ago, they struck up a close, lasting friendship. It was revealed last night at the charity premiere of The Merchant Of Venice.

The Oscar-winning actor, who has been a house guest at Highgrove, was introduced to Camilla Parker Bowles for the first time at the Leicester Square screening. She told him: "How very nice to see you. I've heard so much about you."

Pacino, 64, who wore scruffy trainers with his dinner jacket, later said he did not know whether Charles was a fan of the mafia movies he is famous for. "I will have to ask him later," he joked.

He plays Shylock, a role he has been keen on for a long time. He has already been tipped for another Oscar for his performance.

"It was such a great opportunity," he said. "I did it because of the script. It made Shylock a more tragic figure than just that of the villain. He is a great character, but when you're playing a role that's been done before you hope you can give it your own spin.

"It always felt great doing Shakespeare, even as a young actor. It's such a traditional part of acting, tantamount to musicians doing Mozart. You get to find out so much about the play - and yourself."

The film has a mostly British cast including Jeremy Irons, Joseph Fiennes, The Office star Mackenzie Crook and My Family's Kris Marshall.

Pacino, who said he explained his success through "luck", has said Americans cannot do Shakespeare as well as the British. "The British have encouraged us Americans, but I don't think anybody will ever have the elocution and the taste of words the way some of your actors have," he said. But he admitted to still feeling nerves at premieres. "I can't get used to it, I hope I never do," he said. He said it was an "honour" to have Prince Charles at the screening.

They first met at the royal premiere of his 1997 documentary Looking For Richard. After that Pacino stayed at Highgrove and was reportedly astonished when he bumped into Charles and found him clad in a full-length muslin robe. They have remained in contact with the actor by letter.