The comedian said that he intended to surprise wife Jane Goldman by turning up at her office wearing nothing but a top hat, but his plans went awry when he walked in on the unnamed director.
Speaking on Jamie Oliver's Christmas Lock-In, Ross said: "For some reason a friend of mine bought me for my 50th birthday a white top hat - I think they thought I was going to entertain hen parties in Essex.
"I went down to where my wife was working and just before I got there I took all my clothes off, put on the white top hat and walked in. I didn't know there was a world famous film director in there! Jane shooed me out very quickly."
Goldman has previously worked on scripts for John Madden's The Debt, Matthew Vaughn's Stardust and Kick-Ass. She is currently involved in the screenplay for Vaughn's X-Men: First Class.
Jamie's Christmas Lock-In airs on Thursday at 10pm on Channel 4.