Elizabeth McGovern has hinted her Downton Abbey character Lady Grantham could have her head turned this series - and it may well be by Richard E Grant's art historian.

The actress plays the lady of the house in the ITV period drama, but said her marriage to the Earl of Grantham, Robert (Hugh Bonneville) would suffer the strain of changing times as the social order begins to rebalance.

She told What's On TV: "We continue with the theme established early on that this is a changing world. All the characters deal with that in different ways. And in some ways that creates a wedge between Cora and her husband Robert. He's invested in the world staying the same and she gets annoyed by that.

"There are times in the marriage when Cora feels overlooked, and it creates tension. It makes her open to the charms of someone else."

That someone else could well be suave art historian Simon Bricker, played by Richard E Grant, who turns up at Downton Abbey.

Elizabeth hinted: "We'll see! You find out a bit more about Cora. Cora's open to new ideas and she's changing herself. The marriage will be challenged. People change - and that's when the show gets really interesting."

She added of working with guest star Richard: "Richard and I are old friends. We've worked together before on The Scarlet Pimpernel, and had a really good laugh working on Downton.

"Cora and Simon connect because they both share a passion for art. It gives her a different dimension from just being a mother and Robert's wife."