Cradling her blossoming baby bump as she posed on the red carpet, Hollywood actress Evan Rachel Wood was radiant at the TriBeCa Film Festival opening party.

The expectant star was showing off her spot-on maternity style in a black halterneck dress cinched in at the waist. She paired the simple and elegant number with pointy black Louboutins stilettos and minimal jewellery.

Evan is due to give birth to her first child with husband Jamie Bell in June. "I love that I am going to a cocktail party tonight," she told her fans on Twitter before heading out. "But I can't have any cocktails. It's like a birthday with no cake."

Inside the swanky bash, Evan mingled with fellow celebrities Sienna Miller, Karolina Kurkova and Robert De Niro.

New mum Sienna was showing off her incredible post-pregnancy physique in a flirty floral lace frock.

She posed with Matilda Sturridge, the sister of her fiancé Tom, outside the venue.

Supermodel Karolina was typically stunning in a black trouser suit. A slicked-back do ensured the dramatic number took centre stage while red lips added a pop of colour. The Victoria's Secret angel attended with her husband Archie Drury. 

Robert De Niro's daughter Arena also attended, wearing a green jumpsuit that buttoned down to reveal a lacy bra. Her father is a co-founder of the annual festival which helps promote small filmmakers.

Evan, who married Jamie in a small ceremony in October of last year, announced that she was expecting her first child in January. She has been updating fans about her pregnancy on Twitter.

"I think when you become a parent your radar changes completely," she said earlier this week. "I am seeing New York in a whole new way.

"And suddenly I am aware of how fast and crazy the taxis are. #beingamom."