Anita Dobson's breathtaking new look for BBC Two's part-dramatised documentary Armada: 12 Days To Save England, was as much of a shock to the actress as it will surely be for her fans, who, of course, know her best as EastEnders' troubled landlady Angie Watts.

Temporarily laying her nipped-in waists and trademark curly do to rest ("I still like big hair," she says with a laugh), the actress spent hours in the make-up chair being made-under to play the ageing and pockmarked Queen Elizabeth I.

Set in 1588, the three-part series tells the story of the defeat of the Spanish Armada, with historian Dan Snow explaining the battle and Dobson re-enacting key scenes.

"I had false teeth!" says the 66-year-old, who starred in EastEnders from 1985-1988.

In fact, transforming her into the Virgin Queen was a four-hour process.

"They put this substance on my face and skin, dried it gently with a hairdryer so the skin would stick into wrinkles, and then the make-up artist painted leather spots and pockmarks. There's a shot of me sitting in a dressing gown with the script in my hand, and I look about 111!"

Ageing so dramatically may not be everyone's cup of tea, but Dobson relished the chance to learn more about the Tudor monarch, who she says she came to admire greatly.

"As a woman, and a single woman, she managed to stay on the throne for 50 years," explains the actress.

Anita Dobson

(Anita Dobson and her husband Brian May)

"For half a century, she ruled England, and England thrived under her. What an amazing achievement. She gave up having children, a marriage, because to her, the most important thing was ruling her country.

"She didn't want to lose the power, share it and fight over decisions with another person - i.e. a husband, a man - and so she made that decision to stay the Virgin Queen, and I think that's fantastic."

Although Dobson has been happily married to Queen guitarist Brian May since 2000, women putting their career first is something she can relate to.

Professionally, she is known as Miss Dobson, but "as soon as we go on holiday or anywhere else, I'm Mrs May", she says.

"I like it. We're moving into times now in women's lives, where we can keep our identity much more," adds the actress, who competed in the 2011 series of Strictly Come Dancing.

"So I think it's a good thing that women now, like Elizabeth I, have a strong feeling of self-worth, [that we're] just as important as a single entity [as we are married]."

Born and brought up in London's East End, Dobson had a strong sense of self as a young woman, and despite going to a "very academic school" where opportunities to act were scarce, she followed her own path to amateur dramatics aged 16.

And while many in the biz are divided on the issue of a lack of opportunity for working-class actors, Dobson - who also stars alongside Olivia Colman and Tom Hardy in the upcoming musical film version of London Road (based on the National Theatre production), about the community left behind after five prostitutes were killed in Ipswich in 2006 - is philosophical.

Anita Dobson in make-up

"When I was at drama school, everybody said, 'It's a really tough year', but it's always been tough," she says.

"Each year brings different problems, different economies, different requirements. I think you've just got to make the best of what you've got. It's no good thinking, 'This is worse, I'm a victim of a time where it's more difficult'.

"Life is difficult, whatever career you choose is going to be difficult - I don't think I know anyone who has had a really easy time.

"There are always times where you question yourself; 'I'm not getting anywhere, the work's drying up', and then somewhere out of the blue, something comes in and off you go again."

Understandably, working in a notoriously unstable profession, where rejection is plenty and breakthroughs can take a lifetime, Dobson did wonder whether she should jack it in.

"Before EastEnders, and before that catapulted me into a different place, I do remember my mum saying, 'You've not got married and you've not had any children and you're still pounding the pavements, are you sure you want to do this?'

"So I said, 'All right, I'll come home, I'll take three months off, and I'll have a good think and see what's what'."

Anita Dobson as Queen Elizabeth

But within a week, an offer came through and Dobson, who trained at the Webber Douglas Academy of Dramatic Art and worked on stage for many years before landing her iconic soap role, was "out the door".

"My mum said to me, 'I thought you were going to take some time out?' And I said, 'Well that answers the question doesn't it? Whether I win or whether I lose, this is what I'm going to do'. As soon as I had made that decision, I got EastEnders."

Looking back, she is grateful that it took until she was in her 30s to find fame, and says her age meant she "knew how to bring some colour to Angie because I had been around a bit".

"I had been knocking around in the business for 15 years after drama school," Dobson explains.

"I had done a lot, so although I went from nobody to 'Who's that girl' overnight, for me, it wasn't overnight - it was a long trek through Stepney Green to drama school."

Armada: 12 Days To Save England starts on BBC Two on Sunday, May 24