Legendary British actress looks unrecognisable as she transforms for new Channel 4 drama alongside Steve Coogan

TV star Harriet Walter looks a world away from her usual self as she takes on the role of the first female UK Prime Minister in the new biopic series.

Starring on Channel 4 alongside actor and comedian Steve Coogan, Harriet looks every inch the unmistakable Margaret Thatcher.

In the first teaser images ahead of the two part series, Steve wears a grey suit as he takes on the role of broadcaster Brian Walden.

Yet it's Harriet Walter who steals the show with her usual brunette hair swept back into the politician's trademark bouffant hairstyle.

In one of the images, she can be sat waiting to be interviewed in a dark blue suit with a white shirt which was a typical style for her.

Harriet, who has starred in series such as Succession, Ted Lasso, Silo, isn't the first star to take on the role of the Conservative leader.

In the past, Gillian Anderson won an Emmy for her portrayal in The Crown and Meryl Streep scooped an Oscar 12 years ago for The Iron Lady.

The new series 'Brian and Margaret' will air next year on Channel 4, and is based on political editor and TV producer Rob Burley's book Why is This Lying Bastard Lying to Me?: Searching for the Truth on Political TV.

It's directed by BAFTA-winning Stephen Frears, who also directed A Very English Scandal and Florence Foster Jenkins, Philomena.

During the now infamous ITV interview between Brian and Margaret, the 45-minutes of questioning was credited as being part of the downfall of Margaret and leading to her resignation.

One now famous question saw Brian ask about how her own Conservative cabinet were turning against her in 1989, as Brian asked Margaret whether she was 'off her trolley'.

He said: "You come over as being someone who one of your backbenchers said is slightly off her trolley, authoritarian, domineering, refusing to listen to anybody else – why? 

"Why cannot you publicly project what you have just told me is your private character?"

She answered: "Brian, if anyone's coming over as domineering in this interview, it's you."

The Channel 4 website details the new series as: "When Brian and Margaret came together for their last ever TV interview, little did they know they were about to embark on one of the most famous political exchanges of all time.

"The 45-minute showdown became a national talking point and set in train a series of events that ended with Margaret’s resignation. Afterwards, they never spoke again…"

Speaking of his role Steve said: "It's great to be telling a story from the era of the sorely missed forensic interview - two giants of their time locking horns to determine the future of Britain."

Harriet said: "I have to travel a great distance to reach Maggie Thatcher but with James's brilliant script, Stephen Frears to guide me and Steve Coogan to accompany me I have the dream team to help me achieve it."