'Downton Abbey' Season 3: Hugh Bonneville on Shirley MacLaine, Lord Robert and starched collars
"How funny," he tells Zap2it. "I wonder, if I did it, if I'd be Lord Robert, or if I'd come out as something else. I'd probably come out as [head housemaid] Anna."
Bonneville isn't even sure he'd be good pals with his aristocratic character, who's dealing with a substantially reduced fortune in an England reeling in the wake of World War I.
"He's a reasonable enough guy," he says, "but I don't think he knows much about the outside world. He's quite instinctive about people, sometimes wrongly. He does care about people, I think. He certainly cares about how the estate works and runs. That's what his destiny is, to make sure it's ticking over.
"He's quite keen on fairness, but he's not without his faults and irrational tantrums or whatever. I think he'd be good company for about half an hour, then I think we might run out of things to talk about."
Joining the cast this season is acclaimed actress Shirley MacLaine as Martha Levinson, the very American mother of Lord Robert's wife, Cora ( Elizabeth McGovern), Countess of Grantham. She joins the equally celebrated Maggie Smith, who plays Cora's mother-in-law, the imperious Lady Violet.
"Incredible," says Bonneville of working with MacLaine. "I pinched myself on a daily basis being with Maggie and the cast, but to have two great Dames sitting on either side of me at dinner was amazing.
"They're such incredible actors. I did a two-hander scene with Shirley -- I'll never forget it. I've become blase about Maggie, because it's been three years, but Shirley was great. We adored having her, and I hope she enjoyed it."
Bonneville said the atmosphere on set before MacLaine arrived was "feverish anticipation. Then, when she and Maggie met in the hallway at Downton, they just hugged each other, and it was great. It was rather moving to see these great legends, who, if they did know each other well, they hadn't seen each other for a long time.
"To see them nattering away and bouncing off each other, was great. It was a real privilege. To make it look as easy as she does, when it isn't easy ... It isn't heart surgery, but appearing as natural as she does takes skill. It was great to absorb that close up."
On the personal level, Bonneville says, "Shirley absorbs life. She's an incredible woman. She can talk about Billy Wilder in one breath and aliens the next and reincarnation the next. With Shirley, everything is connected, and that's wonderful."
One thing Bonneville was not looking forward to was donning Lord Robert's formal dinner clothes.
"I hate it," he says. "It's not my style. The suits are fine, but the white-tie and the black-tie dinner jackets -- it's like having a razor blade under your neck. ... It's very difficult to relax in those sorts of outfits, because of the stiff shirts you have, and those high collars."