KATHERINE KELLY admits that fans of Coronation Street might be shocked when they see her in ITV1’s period drama Mr Selfridge. As London socialite Lady Mae Loxley, she wears big frocks and even bigger hats and, although a married woman, has a penchant for beautiful young men.

This is hardly how Corrie viewers remember Kelly as Becky McDonald, last seen jetting off to a new life in Barbados. Now she’s Lady Mae, a former Gaiety Girl, who begins a new life after marrying Lord Loxley and comes to the rescue when Harry Selfridge is looking for funds to launch his new store.

“Watch out for the hats – they can cause an eclipse,” says Kelly. “Lady Mae has to have the biggest and the best. They had to completely change the camera angles to shoot round my hats.

“She was the woman of the time at the top of the ladder. The party that you wanted to go to.

And as a socialite, she knows everybody.”

Since leaving the Street, Rada-trained Kelly has appeared on stage in She Stoops To Conquer at London’s National Theatre and played Kenny Everett’s wife, Lee Middleton, in BBC4 drama In The Best Possible Taste.

“For me, She Stoops was a halfway house between the two because I played the daughter of a landowner who pretended to be a West Country maid,” she says. “In The Best Possible Taste was a story set in the 1960s, 1970s and 1980s. Lee was from Sheffield and blonde. But she wasn’t at all like Becky in her nature.

“Those two jobs have been stepping stones to Lady Mae. If you’ve only seen me in Corrie and think I’m going to waltz into Selfridges with a bottle of cider and smash it all up, then you’re going to be really disappointed.”

She left Corrie to play other different roles, which is exactly what Lady Mae offers.

“I love Becky, but I loved playing Lady Mae as much as I love Becky. I hope that within ten minutes people will forget Becky, forget me and be completely taken up by this show, Mr Selfridge, because that’s what the story did with me.”

Lady Mae is quite “cold and calculating” when introduced in the story but helps Selfridge financially, hinting there’ll be a price to pay at some point.

“It’s not until you know her a bit more and she gets to know the Selfridge family that you find out her history and what she wants,” explains Kelly.

“She’s a suffragette and wants Harry to endorse the cause and actively support it. My character is fictional but the fact that Selfridge’s was pro-women and backed the cause is true. During the riots, the windows didn’t get smashed.

“Yes, it’s a show about Henry Selfridge, but there are some fantastic female characters in it.”

SOME might see ITV as trying to repeat the success of Downton Abbey with another period drama, but Kelly doesn’t think this is anything new. “There’s always a fashion. I remember when I was a teenager Pride And Prejudice came out. We hadn’t had a period drama for ages and were all glued to it and for the next three years Jane Austen series were being made.

“That happens in films and everything. In the Depression big musicals made a comeback.

We’re just in a fashion now of really loving the period dramas and will stay that way until the audience says they don’t want that any more, which will come.

“But I still think there will be plenty more Edwardian period things to come out yet because it’s such a rich period in time.”