Downton Abbey creator Julian Fellowes told a packed Wizo literary lunch on Wednesday that the success of the series had exceeded his wildest imagination.
Baron Fellowes was in conversation with best-selling author Joanna Trollope, who described him as "the saviour of ITV".
He told the 270 diners at St John's Wood Synagogue how he had battled to bring the series to the small screen in the face of scepticism from TV bosses who believed viewers were no longer interested in period dramas.
The former actor - an Oscar winner for his Gosford Park screenplay - said: "The viewing figures were enormous. They went up and up through the second series until we were nudging 14 million viewers, which was extraordinary. Clearly we have an audience beyond our expectations."
Asked if he would like to appear as a character, he replied that he would "love to act again. But the only acting I'm offered at the moment is theatre and I don't really have the time for that. I am an actor more than a writer."
The lunch raised £40,000 for Wizo projects in Israel.