Diane Lane exudes ageless elegance in NYC after 59th birthday... just days before premiere of Feud: Capote vs The Swans where she plays Slim Keith

Diane Lane exuded ageless elegance as she stepped out in Manhattan on Tuesday, one day after celebrating her 59th birthday.

She is currently awaiting the premiere of her upcoming FX show Feud: Capote vs. The Swans, the latest Ryan Murphy confection.

Amid a star-studded cast including Naomi Watts, Demi Moore and Chloe Sevigny, Diane features as the glamorous New York socialite Slim Keith.

When she emerged on Tuesday in the city that never sleeps, Diane proved that she herself is no slouch in the arena of New York chic.

The Unfaithful star tucked a snappy collarless blouse into a split print skirt, which was cinched in with a belt to emphasize her petite frame.

Diane Lane exuded ageless elegance as she stepped out in Manhattan on Tuesday, one day after celebrating her 59th birthday

She is currently awaiting the premiere of her upcoming FX show Feud: Capote vs. The Swans , the latest Ryan Murphy confection

When she emerged on Tuesday in the city that never sleeps, Diane proved that she herself is no slouch in the arena of New York chic

Pounding the pavement in a sleek black pair of high-heeled boots, Diane let her luxurious hair tumble over her shoulders in sumptuous waves.

Premiering January 31, Feud: Capote vs. The Swans stars Tom Hollander as Truman Capote, in the story of his dramatic exile from the New York beau monde.

Truman charmed his way into the highest echelons of New York society, becoming the confidante of many of its top trophy wives, whom he called his ‘Swans.’

The break came in 1975, when he published a now infamous short story in Esquire called La Côte Basque, 1965, dishing the dirt on his extremely thinly-veiled friends.

Furious and wounded at his betrayal, the Swans closed ranks and ejected him from their circle, much to Truman’s shock and dismay.

‘What did they expect?’ he moaned. ‘I’m a writer, and I use everything. Did all those people think I was there just to entertain them?’

Diane plays the acid-tongued society maven Nancy ‘Slim’ Keith, who husband-hopped from Howard Hawks to Leland Heyward to an English baron.

In La Côte Basque, 1965, Slim is rendered as ‘Lady Ina Coolbirth,’ an American who has married her way into the British aristocracy and spends the story gleefully spilling her dearest friends’ nastiest secrets.

Premiering January 31, Feud: Capote vs. The Swans stars Tom Hollander as Truman Capote, in the story of his dramatic exile from the New York beau monde

Diane plays the acid-tongued society maven Nancy ‘Slim’ Keith, who husband-hopped from Howard Hawks to Leland Heyward to an English baron

In Truman’s short story La Côte Basque, 1965, Slim is rendered as ‘Lady Ina Coolbirth,’ who spends the piece gleefully spilling her dearest friends’ nastiest secrets

The real Slim Keith is pictured on her porch in Lyford Cay, New Providence Island in 1974, the year after Truman’s scandalous short story was published

Meanwhile Naomi Watts features as Babe Paley, the wife of CBS president Bill Paley and a woman widely regarded as one of the most beautiful and stylish in New York.

Of all the Swans, Babe was among those most hurt by the Esquire piece, inasmuch as she had regarded Truman as a close and trusted friend.

Compounding her misery, the story was published at a time when Babe was battling what turned out to be a terminal bout of lung cancer.

La Côte Basque, 1965 includes an anecdote in which a stand-in for Babe’s husband has an adulterous one-night stand with a stand-in for Maria Harriman, the wife of diplomat-turned-New-York-governor Averell Harriman.

In the Esquire piece, the governor’s wife has her period all over the tycoon’s sheets, forcing him to spend all night trying to remove the stains before his wife gets home.

Meanwhile Naomi Watts features as Babe Paley, the wife of CBS president Bill Paley and a woman widely regarded as one of the most beautiful and stylish in New York

Chloe Sevigny meanwhile plays horsewoman and fashion plate CZ Guest, who remained friends with Truman after the furor over the Esquire story

Calista Flockhart plays Jackie Kennedy’s sister Lee Radziwill (pictured), with Molly Ringwald as Johnny Carson’s second ex-wife Joanne

Chloe Sevigny meanwhile plays horsewoman and fashion plate CZ Guest, who remained friends with Truman after the furor over the Esquire story – an act of loyalty possibly made easier by the fact she was not turned into one of his characters.

Calista Flockhart plays Jackie Kennedy’s sister Lee Radziwill, with Molly Ringwald as Johnny Carson’s second ex-wife Joanne.

Demi Moore plays Ann Woodward, a social climber who became a scandalous figure when she killed her wealthy husband at home with a shotgun and avoided having to go to trial by insisting she thought he was a burglar.

When she got word that Truman’s story was about to air out her past all over again and suggest she murdered her husband deliberately, Ann committed suicide.

‘Well, that’s that,’ her mother-in-law remarked. ‘She shot my son, and Truman just murdered her, and so now I suppose we don’t have to worry about that anymore.’