Inside the tragic true story of Princess Margaret's marriage to Antony Armstong-Jones.

Following their wedding in 1960, the first ever Royal wedding to be televised, Princess Margaret and Antony Armstrong-Jones were known as one of Britain’s most glamorous couples.

But behind the scenes, their marriage was incredibly different.

While Netflix series The Crown sees the pair meet at a party in 1958, photographer Antony already had a relationship with the British royal family long before meeting Margaret.

But when Antony was commissioned to photograph Margaret, a secret relationship between the two began.

The Queen’s sister visited Antony in disguise at his studio and they were able to spend weekends together at a “safe house” of friends.

“Nobody knew about their relationship, there wasn’t a whisper about it,” royal biographer Anna de Courcy told Town and Country Magazine.

“She would see him in secret at his studio and yes, he would join her at parties, but no one could pinpoint which man she was interested in,” she explained.

But while the pair were described as being "besotted" with each other, Antony continued to conduct multiple affairs right up until their engagement.

Not only was the photographer involved with actress Gina Ward and actress Jacqui Chan, he also fathered an illegitimate child with his close friend, Camilla Fry.

Polly Fry, who was born just weeks after Antony wed Princess Margaret, completed a paternity test in 2004 which confirmed Antony was the father.

Despite Antony's countless affairs, the pair became engaged on February 26, 1960.

Although the Queen happily gave her approval for the engagement, she requested they delay the official public announcement until after the birth of her son Prince Andrew.

Their wedding, which followed on May 6 1960, was attended by Antony's two ex-wives as well as his former lover, Jacqui Chan.

The tradition-breaking marriage saw Antony become the first commoner to marry into the British Royal family in over four centuries.

After returning from their six-week honeymoon, Antony was given the title Earl of Snowden. And shortly after in 1961, the couple welcomed their first child, their son David, before welcoming their daughter Sarah three years later.

But while their marriage appeared glamorous and happy from the outside, the reality was much different.

A new BBC documentary, Princess Margaret: The Royal Rebel, details the reality behind the couple's rocky marriage, with friends of Margaret describing Antony as an "absent" and "uncaring" husband.

A close friend of the royal, Jane Stevens shared that Antony stopped supporting his wife's royal duties very early on in their marriage.

"It was naughty in a way because he married Princess Margaret, and therefore knowing who he was marrying, he should have helped her, but he didn't," she said.

"He stuck with the job he had [photography], which had nothing to do with the royal family, and that was hard for her."

Antony's decision to return to photography was largely inspired by his disinterest with royal life.

Laura Brodnik interviews Vanessa Kirby about her role as Princess Margaret in The Crown Season 2.

"Tony loved all royal things at the beginning, but then he got bored and off he went," another friend of Margaret's, Lady Anne Glenconner told the BBC.

Working for the Sunday Times, Antony's work pulled the couple apart as Antony was having flings on work assignments while Margaret reportedly began to bring lovers to the home while he was away.

She had an affair with her daughter's godfather Anthony Barton and was rumoured to have been romantically involved with Mick Jagger, actor Peter Sellers and Warren Beatty.

While they were together, Antony would constantly make digs at Margaret.

"At parties, he would cut her off in mid-conversation. “Shut up and let someone intelligent talk,” was one such sally. Another note, from husband to wife, apparently read: “You look like a Jewish manicurist and I hate you," Stephen Bates wrote in The Guardian.

The doomed relationship eventually came to an end in 1976, when they separated.

The couple then became the first royal couple to divorce since 1540, when they finalised their divorce in 1978.

Although Lord Snowden went on to remarry Lucy Hogg (the couple separated in 2000), Margaret never remarried until she died in 2002.