The genius behind ITV sensational hit period drama, Downton Abbey, Nigel Marchant, has revealed that he wants the show to end on a high-note.

The hit drama, which  has found huge success in the US as well and has even been spoofed by Jimmy Fallon on his late night US show, has always had an expiry date attached, with Marchant previously commenting that he would never let it over run with any of his other projects on the period time line.

Speaking at the Monte Carlo Television Festival Nigel commented: “I know Julian’s mentioned in the past there’s a five-year span to it and we certainly want to end on a high and we’re all of conscious of that.

“I think that’s the joy of doing this series at the moment – we’re still upping the ante. The scripts are fantastic. So I don’t think anyone would put a line in the sand to say how much we’re actually going to do.”

“We sat there and made a show we were very proud of but we’ve all done that before on many other shows,” Marchant added. “You never know how it’s going to go down.

“It appeals to such a wide audience…We tried to create a peer drama that was shot in a new style, that was shot in a more modern style, and I think we managed to get that across.

“There’s a similarity to American shows like The West Wing walking around, and we try to keep that energy downstairs. And then you show the difference upstairs. But I don’t think any of us expected it to have the impact it had.”

Downton Abbey is due to return for its third series in September on ITV1 in the UK and in January 2013 on PBS in the US with the addition of famous  actress Shirley MacLaine  guest starring as Lady Grantham’s mother.

Speaking at the same event,  Allen Leech (Tom Branson) described  what it was like working with MacLaine.

“She’s finished filming now but hopefully she’ll come back,” he said. “But she was absolutely amazing and just a life force. She arrived on set the first morning and what she was filming, you were just drawn into it.

“It’s a living legend, you know, like Maggie [Smith] as well, and just the two of them talking… Shirley would turn and she’d go, ‘When I opened for Sinatra…’ and you go, ‘OK…’ You could write a book based on what was said!”

“I don’t know if it’s a book she’d want written. It was all stories like that. I just found it fascinating.

“The Rat Pack in New York and LA and the stories of the parties that she’d go to and the people that would be there. And just the fact that her career spans so many… She’d tell stories and she’d mention Meryl Streep and then it’s just amazing.

“I just found that fascinating. So maybe it’s a book I should write for myself.”

Downton Abbey is due to return for its third series in September on ITV1 in the UK and in January 2013 on PBS in the US