Actor Jon Hamm has revealed that the relationship between Mad Men characters Don Draper and Joan Harris will be explored in greater detail as the series progresses.

The actor, who plays womanising ad executive Draper in the drama, made his comments at the Curzon Mayfair last night as part of a Bafta interview with Jo Whiley.

When asked why Draper has never made a pass at office vixen Joan, played by Christina Hendricks, Hamm responded: “Who says he hasn’t?”

He continued: “The Don/Joan dynamic is something that we do explore, and don't take this the wrong way, but we do explore as the show goes on.

"They have worked together for a long time, they know one another very well and I'll leave it at that."

Hamm also hinted that there was hope for his character, despite the tumultuous last series of the show, in which he lost his friend Anna and shocked colleagues with a spontaneous proposal to new secretary Megan.

“[Anna's death] may have caused some tectonic shift in Don, maybe one of the reasons we saw the proposal. It's not a mistake that he gives Megan Anna's ring, he did not give that to Betty, but I think that there is hope," he said.

Additionally, Hamm revealed that there would be at least a further three series of Mad Men, and that the first episode of the upcoming fifth season will be two hours long.

Mad Men’s fifth series will begin airing on Sky Atlantic on Tuesday 27 March.