The wedding dress is the best-kept secret since Kate Middleton and her mum popped into Alexander McQueen’s studio.

But after two series of will-they-won’t-they, Downton Abbey’s Lady Mary and Matthew Crawley will get their big day.

And Michelle Dockery, who plays Lady Mary, says it made her start thinking about marriage for real.

Michelle, 30, says: “I felt a bit like Kate Middleton with all the security, but we didn’t want people seeing the dress before the day. I’d never worn a wedding dress – I’ve never filmed an on-screen wedding before. I loved it.

“It’s a truly stunning dress and I’m sure people will make some comparisons with the royal wedding. As we arrived at the church and stepped out of the carriage the crowds were just amazing, with all these supporting artists cheering us on.”

The actress, who lives with her architect boyfriend of three years in London’s trendy Clerkenwell, added: “It felt strange, you get those nerves. It did make me think a little bit about what it would be like to be a bride.”

The details of the much-anticipated wedding were so secret even Michelle’s mother was kept in the dark.

She said: “My mum doesn’t know we get married this time.

“We have to keep storylines from friends and family, and that is hard sometimes. But also I don’t want to spoil it for them because they watch it as fans.”

But as Dan Stevens, who plays Downton heir Matthew, says, after the couple got engaged in the Christmas special, it was about time.

“It was on the cards, wasn’t it?” he laughs. “I think we’d have been hard pushed to stretch out the will-they-won’t they storyline much longer. But there’s still some thrills and spills, it’s not all plain sailing.”

And the 29-year-old agreed their TV nuptials felt like a celebrity bash: “There was quite a lot of security and it was crawling with paparazzi.

“I didn’t actually see Michelle in the dress till she walked down the aisle which was pretty realistic.”

And after so many ups and downs, Michelle says: “What’s different for us now is we’ve been playing those scenes when so much is unsaid, and it’s all stolen moments. Now they’re finally settled.”

But that doesn’t mean life will be perfect. Michelle adds: “Lady Mary is very happy but they have their teething problems at the start.”

One new twist for the characters, who have been an on-off couple since the start of the first series in 2010, is that they have bedroom scenes. “It doesn’t get pornographic but there’s a newly-wed undercurrent,” Dan teases.

In real life he already knows exactly what it feels like to get hitched. He married actress Susie Stevens, 36, in 2009 and they have a two-year-old, Willow, with a second baby on the way.

“My wife doesn’t mind me marrying someone else,” he laughs. “My own wedding was better.”

And while young Willow is normally in bed by the time the show is on, she’s still a fan. “My daughter likes that Daddy works in a castle,” he says.

Writer Julian Fellowes was delighted to marry off his two leading characters. “I think it would have been a bit sad if we’d deprived them of it again,” he says. “I think there’s a moment when you’ve teased long enough.”

Down-to-earth Michelle, whose best friend remains her oldest school pal, says that being in Downton is opening doors for her. The show is hugely popular in the US and has been nominated for a staggering 16 Emmys.

“It’s great that America has taken the show to its heart,” she says.

Her next role is in BBC drama Reckless, but a move to America is looking likely. Earlier this year she was on the cover of Vanity Fair and offers are rolling in.

“It certainly feels as though there are more opportunities for us over there,” she says. “I love spending time there.”

The new series of Downton itself gets back to its roots, says Dan, who admits he felt it lost its way during the last run when it dealt with the First World War.

“I thought some of the criticism was very founded,” he says. “The problem was, if we’d ignored the war we’d have been churlish but we couldn’t do it full justice because we weren’t making a war drama.

“The audience didn’t tail off but critically I can understand why people found problems with it. One of the things I enjoyed the most were the small dramas about holes in shirts and unpolished candlesticks.”

Hugh Bonneville, who plays the Earl of Grantham, thinks this third series is the strongest yet. “The surprises in it are so strong,” he said.

One of those is the death of a major character. The Earl is also grappling to save Downton after losing his family fortune in a railway investment.

Could it be the end of Downton? Unlikely, as Fellowes is already dreaming up ideas for the fourth series next year.

Forbidden love is in the air

The third series of Downton will be packed with love affairs, crushes and new relationships.

Half the downstairs staff fall for new kitchen maid Ivy instantly – much to the annoyance of Daisy.

Middle daughter Lady Edith will do her very best to persuade her beau Sir Anthony Strallen that she is marriage material.

And nasty footman-turned-valet Thomas will endeavour to find happiness. Rob James-Collier, who plays the gay character, says: “It’s a very emotional storyline and goes some way to explaining why he is how he is. Being a homosexual man in Edwardian times was against God and you could go to prison for it. It’s a burden and the audience will hopefully empathise with him.”

The former Coronation Street star hints that Thomas embarks on a “forbidden” love affair.

So could it be with handsome new footman Jimmy Kent, played by Ed Speleers?

Rob reveals: “Thomas takes him under his wing and looks after him. Knowing Thomas and knowing he has a preference for a certain type of person in life, I think Jimmy fits that bill perfectly… ”

Meanwhile Lady Edith could become the last of the three sisters to marry.

Elizabeth McGovern, who plays her mother Cora, said: “They all get their moment, they really do. It either comes at the beginning or it comes later.”

http://www.mirror.co.uk/tv/tv-news/i-felt-like-kate-middleton-says-1269875