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 timeless elegance as she stepped into Manhattan on Tuesday, a day after celebrating her 59th birthday.

She is currently awaiting the premiere of her upcoming FX show Feud: Capote vs. The Swansthe last Ryan Murphy ready-to-wear.

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

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

The Unfaithful star tucked a sassy collarless blouse into a split-print skirt, which was fastened with a belt to emphasize her petite frame.

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

When she showed up Tuesday in the city that never sleeps, Diane proved she’s no slouch in the arena of New York chic herself

Diane pounded the pavement in a tight black pair of high-heeled boots, letting her luscious hair tumble over her shoulders in luscious waves.

Feud: Capote vs. The Swans premieres on January 31 with Tom Hollander as Truman Capote, in the story of his dramatic exile from New York’s socialite.

Truman worked his way into the highest echelons of New York society and became the confidante of many of its top women, whom he called his “Swans.”

The breakthrough came in 1975, when he published a now infamous short story in Esquire called La Côte Basque, 1965, in which he pranked his extremely thinly veiled friends.

Enraged and wounded by his betrayal, the Swans closed ranks and drove him from their circle, much to Truman’s shock and dismay.

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

Diane plays the acerbic society expert Nancy ‘Slim’ Keith, who, as the husband of Howard Hawks, hopped to an English baron via Leland Heyward.

In La Côte Basque, 1965, Slim is depicted as ‘Lady Ina Coolbirth’, an American who has assimilated into the British aristocracy and spends the story happily spreading the dirtiest secrets of her dearest friends.

Feud: Capote vs. The Swans premieres January 31 with Tom Hollander as Truman Capote, in the story of his dramatic exile from New York’s socialite

Diane plays the acerbic society expert Nancy ‘Slim’ Keith, who, as the husband of Howard Hawks, hopped to an English baron via Leland Heyward

In Truman’s short story La Côte Basque, 1965, Slim is depicted as ‘Lady Ina Coolbirth’, who spends the play happily spreading the dirtiest secrets of her dearest friends.

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 stars as Babe Paley, the wife of CBS President Bill Paley and a woman widely considered one of the most beautiful and stylish in New York.

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

To add to 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 contains an anecdote in which a stand-in for Babe’s husband has an adulterous one-night stand with a stand-in for Maria Harriman, wife of the diplomat-turned-governor of New York, Averell Harriman.

In the Esquire piece, the governor’s wife gets her period on the magnate’s sheets, forcing him to spend the night trying to remove the stains before his wife comes home.

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

Chloe Sevigny, meanwhile, plays horsewoman and fashion recorder 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 model CZ Guest, who remained friends with Truman after the furor over the Esquire story — an act of loyalty that may have been made easier by the fact that she wasn’t 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 murdered her wealthy husband at home with a shotgun and avoided a trial by insisting she thought he was a burglar.

When she learned that Truman’s story was about to re-expose her past and imply that she had deliberately killed her husband, Ann committed suicide.

“Well, that’s that,” her mother-in-law remarked. “She shot my son, and Truman just killed her, and now I don’t think we have to worry about that anymore.”