As many will already know, Princess Margaret married photographer Antony Armstrong-Jones (later the Earl of Snowdon) on 6 May 1960. By the early Seventies, though, the couple had drifted apart – and the press later fell upon her “loving friendship” with Roddy llewellyn, a man 17 years her junior, portraying her as a predatory older woman and Llewellyn as her toyboy lover

When Llewellyn left on an impulsive trip to Turkey, Margaret became emotionally distraught and took an overdose of sleeping tablets. “I was so exhausted because of everything,” she later said, “that all I wanted to do was sleep.” As she recovered, her ladies-in-waiting kept Lord Snowdon away from her, afraid that seeing him would distress her further – and the couple later released a press release, publicly acknowledging that their marriage had irretrievably broken down.

It was a decision which saw her damned as a “royal parasite” and a “floozie” – and even sparked calls from politicians to have her removed from the civil list.

With all of the above to contend with, it’s only natural that HBC is nervous about taking on the role.

“We’re completely terrified,” Bonham Carter said in a statement. “I think also because the first two seasons were such a success, we have the onus of inheriting the responsibility of doing justice to all these genuinely famous people, and then on top of it, inheriting them from this previous generation of actors who’ve done such good jobs.”

She continued: “I’m not sure which I’m more terrified about — doing justice to the real Princess Margaret or following in the shoes of Vanessa Kirby’s Princess Margaret.

“The only thing I can guarantee is that I’ll be shorter [than Vanessa].”

The Crown: how will Helena Bonham Carter play Princess Margaret in series 3?