Sports icon David Beckham suffered a sleepless night before filming an appearance with the reunited cast of hit U.K. comedy Only Fools And Horses as he struggled to learn his lines. The retired soccer star is set to grace the small screen with Sir David Jason and Nicholas Lyndhurst in a sketch for Britain's Sport Relief charity telethon. The skit reunites the show's characters for the first time in more than a decade, and Beckham, a huge fan of the original comedy, admits he struggled with the script and was wracked with nerves the night before the shoot. He tells British magazine the Radio Times, "The day of filming started off with a slightly sleepless night, going over my script. The thought of being on set with Nicholas and David was obviously very nerve-racking. I woke up that morning with my script on my chest. "I've never done anything like this before, especially with two people I'm really in awe of and have been for many years. It wasn't just about learning the script, it was about delivering it; saying the right things at the right time." The show, which ran from 1981 to 2003, focuses on two hapless market trader brothers from London. The sketch will air as part of the Sport Relief telethon on 21 March (14).