Julian Fellowes says it was a "logistical nightmare" getting the cast together for the 'Downton Abbey' movie.
The film sequel to the ITV period drama has seen fan favourites including Lady Mary Talbot (Michelle Dockery), Robert Crawley, Earl of Grantham (Hugh Bonneville), Edith Pelham, Marchioness of Hexham (Laura Carmichael) and Violet Crawley, Dowager Countess of Grantham (Maggie Smith) return but creator Fellowes admits it was tough getting everyone together to film the scenes because they're all so busy.
Speaking on CBS Sunday Morning, he said: "To the wider public, none of the young ones were really known, and now they're all famous around the world. They were doing shows on Broadway and movies and series in Hollywood and plays in London and God knows what. They all had to be extracted for a kind of 12-week period, and I think that was a logistical nightmare, but we happily got there in the end."
Meanwhile, it was recently revealed that the 'Downton Abbey' cast are keen on a movie sequel.
Allen Leech - who reprises his role as Thomas Branson - said: "What I love about what Julian always does is when it looks like he's finishing a storyline, he's actually starting one.
"It would be very interesting to see what would happen. I think we would all be up for it. It all comes down to how this one does. If people really love it and there really is an appetite, then why wouldn't we do it?"
Whilst Fellowes is open to it, he wants to wait to see what the reaction to the first movie is before deciding on a sequel.
He said: "I just feel I have to wait for the public's response to the movie and see, did they really like it? Has it gone well?
"It's a combination of the [box office, audience buzz] all of it, to be honest, and then you get a picture of whether this movie landed. I think you can get a sense of whether it worked or not. And if we do get that sense, then we will have that conversation."