If Matthew Rhys didn’t appreciate the effect a particular sartorial choice might have in the past, then he certainly does now. The item in question is the billowing white shirt he wears for his role as the iconic Mr Darcy.

“I’ve been quite surprised with the sort of reaction it gets,” says the Welshman.

“Everyone loves the shirts. They go, ‘Oh, romance. Take me away, dream man!’”

That said, the actor’s all too aware that many people relate Darcy to Colin Firth’s memorable interpretation (notably, that emergence from the lake) in the Nineties TV adaptation of Pride And Prejudice.

“I’ve noticed quite quickly that people go, ‘Are you playing Colin Firth?’” jokes the 39-year-old. “And everyone asks about the lake and the shirts and you say: ‘I’m not doing that’.”

He is, in fact, playing Darcy in Death Comes To Pemberley, a small-screen adaptation of the bestselling novel by Oxford-born PD James, which is set a few years after Jane Austen’s Pride And Prejudice.

Darcy and Elizabeth (Anna Maxwell-Martin) have been married for six years and are parents to two boys, but the peace of their magnificent home Pemberley is shattered with the arrival of Elizabeth's sister Lydia (Doctor Who’s Jenna Coleman).

She appears screaming that her husband George Wickham (John Goode) has been murdered and, as the family becomes caught up in the ensuing investigation, a web of secrets and deceit threatens to encompass all that the Darcys have built.

“He’s a very different Darcy, so in that respect the comparisons [to Firth] can’t be held up. I’m safe, they can’t judge me!” says Rhys, laughing.

“But when a murder happens and Darcy’s world’s turned upside-down again, very old themes from Pride And Prejudice come back to haunt him, such as concern for his lineage and good name.”

He read Jane Austen’s classic novel in preparation. It provides the foundation for his character, even if Darcy has softened from the rude, arrogant man originally depicted.

“I think he’s a very sensitive man, a very layered bloke.”

Much like himself? “Oh yes, we’re both moody, misunderstood, complex, not too bright and good in a shirt,” says Rhys, grinning.

A greater challenge than tearing women’s eyes away from his exposed chest, though, was mastering the accent.

“It’s harder for me to play a posh English man than it is an American, because I sound so thick. I’m sure I’m in for a bit of a sledging for this one.”

His family already find it hysterical that he’s playing one of literature’s brooding figures, he admits. “Here’s this great upper-class gent with great decorum and pheasants, and I’m still the oik to them.”

For that reason, the actor, who’s been LA-based for almost a decade, says he won’t be watching the drama when he returns to Wales for Christmas.

“No, that’s just setting yourself up for ribbing. ‘Look at the way you walk. God, you sounded dead Welsh then’.”

Death Comes To Pemberley begins on BBC One on Thursday, December 26