The Crown's new stars Olivia Colman and Helena Bonham Carter step out at glamorous season premiere

Screen sisters Olivia Colman and Helena Bonham Carter stepped out in black last night for the premiere of the third series of The Crown.

Colman, 45, who plays The Queen in the Netflix show, wore a long fishtail gown on the red carpet, while Bonham Carter, 53, who plays Princess Margaret, chose an elaborate dress, complete with a puffy tulle skirt and blue feathered detailing. Erin Doherty, who plays Princess Anne, was also at the Curzon Mayfair yesterday.

Other TV shows are mere period dramas. With its obsessive attention to detail, saturated in the colours and fashions of the Swinging Sixties, Netflix's true-life royal saga The Crown is a marvellous recreation of an era, the Daily Mail reports.

Watching the lavish serial, as it returns for a third season, feels like a drug-tinged hallucination of Britain's not-so-distant past.

Core cast members Tobias Menzies (Prince Philip), Olivia Colman (Queen Elizabeth) and Helena Bonham Carter (Princess Margaret) pose at the premiere. Photo / Getty Images

Inside London's palaces, starched flunkies march up red-carpeted flights of stairs, while footmen in brocaded uniforms stand to attention below the portraits of monarchs. But shift a book on a shelf to peep through the spyhole behind it, and you might see Princess Margaret (Helena Bonham Carter) in her private rooms, draped over a jazz pianist and crooning Cole Porter songs while her sozzled friends lounge around in a haze of marijuana smoke.

Meanwhile, the Queen and Prince Philip are watching TV at breakfast. He's wincing while she scrapes margarine over a dry triangle of toast with a repressed, rhythmic fury. After four children, their marriage has settled into a suburban pattern: it's like watching sitcom couple Terry and June the morning after a bad row.

Olivia Colman as the Queen affects a clipped upper-class accent but that doesn't disguise for a moment that this most emotional of actresses is incapable of an artificial performance.

Claire Foy, her predecessor in the role, was frequently icy and distant. If Colman has a fault, it is that she is too warm, too human. Sitting beside Winston Churchill's bedside as the Grand Old Man drifts in and out of consciousness, her eyes are brimming. When she confronts her new prime minister Harold Wilson she can't keep the mistrust out of her eyes — and when Colman gives you a dirty look, you feel it.

The transition from Fifties to Sixties and an entirely new cast is elegantly handled. A new profile portrait has been commissioned for the Royal Mail's stamps, to reflect the fact that the Queen is no longer a very young woman: she was just 25 when she ascended to the throne.

Now approaching 40, she describes herself as an "old bat" — and adds, "Age is rarely kind to anyone." As she says it she is looking at two stamps, featuring Foy on the left and Colman on the right. Very clever.

The transition from Fifties to Sixties and an entirely new cast is elegantly handled. Photo / Netflix

Margaret was previously played by Vanessa Kirby. To help us adjust, when we first meet Bonham Carter she is sprawled over her bed wearing a silk eye mask. Of course, she might simply have a colossal hangover. More than has been the case in previous series, each episode this time centres on a specific event in British history — a spy scandal, the Aberfan disaster, the investiture of the Prince of Wales, a miners' strike.

Writer Peter Morgan shifts the focus away from the troubled marriage of the Queen and Prince Philip, and Margaret's torrid love life, to give a wider impression of national life. Modern resonances are louder: we begin with a general election, and a dying Churchill's warning of "the cold wind of socialism blowing through these lands".

Members of The Crown family on the red carpet, including creator Peter Morgan (second left), Erin Doherty (Princess Anne, in red), Jason Watkins (former Prime Minister Harold Wilson, second right) and Josh O'Connor (Prince Charles, far right). Photo / Getty Images

But these are not The Crown's special attraction. It has become Netflix's most successful serial (and its most expensive, with this series rumoured to have cost NZ$204 million) because of its portrayal of royal marriages.

These are their private lives — as Philip (Tobias Menzies) emphasises when he snaps "eyes left!" at a palace official before giving his wife a smacker on the lips.

What The Crown offers is a privileged and illicit glimpse of things we were never meant to see and might only have imagined. Enjoy!

The Crown is on Netflix from Sunday, November 17.