She's expecting baby number two to arrive in early 2018.

And Nicky Hilton, 34, showed off her baby bump as she strutted through New York City in a comfortable hoodie that tightly cradled her growing baby bump on Thursday.

The pregnant socialite's appearance came after she took to Instagram to share a nostalgic childhood snapshot of her and sister Paris Hilton, 36, in matching pink dresses.

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Bumping around: Nicky Hilton, 34, showed off her baby bump as she strutted through New York City in a comfortable hoodie that tightly cradled her growing baby bump on Thursday

The hotel heiress - who is married to British banking heir James Rothschild, 32 - bundled up in a Supreme sweatshirt and a cozy-looking khaki fur-lined parka jacket.

Vamping up her maternity look, Nicky strutted her stuff in leather skinny pants and Nike high-top sneakers.

The mother-of-one wore her blonde locks pulled back in a tight ponytail and sheltered her eyes from the winter sunshine with dark shades.

Nicky appeared to be make-up free for her day out, as she carried a cup of takeout Starbucks Coffee.

Keeping cozy: The hotel heiress - who is married to British banking heir James Rothschild, 32 - bundled up in a Supreme sweatshirt and a cozy-looking khaki fur-lined parka jacket

Throwback Thursday: The pregnant socialite's appearance came after she took to Instagram to share a nostalgic childhood snapshot of her and sister Paris Hilton, 36, in matching pink

The heiress was feeling sentimental on Thursday as she posted a photo of her and her sister in matching pink gowns at Christmas time when they were young.

Alongside the sweet snap, she wrote: 'Mom always loved a twinning moment #ThrowbackThursday.'

In an interview with Us Weekly, Nicky shared a few kind words about her sister while talking about her gender reveal plans.

'You know what? I would be happy with either, but I love having a sister. With a sister, you have a best friend for life," Nicky said.

Chic in the city: Vamping up her maternity look, Nicky strutted her stuff in leather skinny pants and Nike high-top sneakers

Girl about town: . The mother-of-one wore her blonde locks pulled back in a tight ponytail and sheltered her eyes from the winter sunshine with dark shades

'But a boy would be really cute, too. I’m thrilled with whatever.'

Due to Nicky's flying restrictions, the entire Hilton family will be gathering in New York, rather than Los Angeles, for Christmas.

The family typically spend the holiday season at the Hilton's Bel Air mansion.

Nicky and her husband of two-and-a-half years, James Rothschild, are already doting parents to baby daughter Lily Grace, 17 months, with their second child set to arrive in early 2018.

Best friends: Nicky shared a few kind words about her sister while recently talking about her gender reveal plans (pictured at New York Fashion Week in September)

DailyMail.com exclusively revealed Nicky was expecting her second baby this summer.

An insider claimed she and elder sister Paris love being close in age, so the family are all very excited at the news.

'It's Lily's first birthday July 8 so they are excited,' the source revealed. 'They always wanted to give Lily-Grace a sibling close in age, like they both have.'

The Hilton hotel heiress married British James in a lavish ceremony at the Kensington Palace Orangery in London in July 2015, surrounded by the creme de la creme of British society, as well as their friends and family.