Richard E Grant has admitted he suffered from first day nerves when he joined the cast of Downton Abbey as a guest star.

The Withnail And I actor crops up in the ITV period drama this series as art historian Simon Bricker, and revealed that despite being a Hollywood star he still felt anxious about the new job.

He told Radio Times: "It was like being summoned to step into the television and join the characters of my favourite programme - crossing the fourth wall, as it were, and becoming part of the story. That's what it felt like being at Highclere Castle (where the show is filmed).

"Everything is incredibly familiar from having watched Downton Abbey on TV for four years, and yet here I was among them pretending to be a character. It was absolutely surreal."

Richard makes his Downton debut on ITV on September 28.