Excited aunt-to-be Paris Hilton cradles sister Nicky's baby bump

Paris Hilton couldn't be more excited about becoming an aunt. Stepping out with pregnant Nicky on Tuesday night (Apr. 12), the socialite excitedly cradled her sister's blossoming baby bump as they arrived at the Foundation Fighting Blindness world gala in New York.

The siblings attended the event at Cipriani Wall Street together, and while Paris looked glamorous in a black fishtail gown, Nicky showcased her impressive maternity style in a red floral dress and Lorraine Schwartz jewellery.

TAP TO VIEW GALLERYParis Hilton touching Nicky Hilton's stomache Paris Hilton patted her sister Nicky's baby bump

The mom-to-be, who is believed to be around six months pregnant, had an unmistakable glow and wore her hair tied back into a sleek ponytail.

The event was held in order to raise money to support Foundation Fighting Blindness, which drives research to provide preventions, treatments and cures for people affected by eye conditions. It was attended by a number of famous faces including Leonardo DiCaprio, Princess Maria-Olympia of Greece and model Crystal Renn.

Paris appeared to have enjoyed her evening out and shared a photo of herself with Nicky on Instagram, which she captioned: "Love my beautiful sister."

Paris Hilton and pregnant Nicky Hilton at Foundation Fighting Blindeness Nicky's first child is believed to be due in the summer.

Nicky's pregnancy was confirmed in January, six months after she married James Rothschild in a lavish London wedding. The couple were said to be "over the moon" at the happy news.

CELEBRITY BABIES DUE IN 2016

"Nicky is very excited to become a mom, she is feeling great!" a source told People at the time. "They've just begun telling close friends and family. Nicky and James are over the moon!"

The happy news capped off an incredible 12 months for Nicky and James, who tied the knot in front of their family and friends at The Orangery in Kensington Palace in July. The beautiful bride stunned in a bespoke lace Valentino dress, and enlisted her sister Paris Hilton as her maid of honour.

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