UNICEF’s annual snowflake ball summoned the stars in support of the organization\'s mission to save children\'s lives. The black tie gala took place at Cipriani in New York last night, where celebrities showed us how to work high-end gowns in winter. Uma Thurman, Katy Perry and Selena Gomez all opted for streamlined dresses in midnight tones in an attempt to steal the show. Uma Thurman looked voluptuous in a form-fitting deep blue velvet gown. The new mother is getting out and about after finally releasing the name of her baby (Arkadina) last month. Katy Perry also attended wearing a dark blue Naeem Khan gown covered in cut-out lace which complemented her alabaster complexion and raven hair perfectly. She went for a demure down- do with a centre parting and understated make-up. Newly single Selena Gomez wowed in a revealing black and gold Dolce and Gabbana halter-neck gown, complemented by full, wavy hair, rosy cheeks and smoky eyes. According to the UNICEF website, the fundraising event has raised over $16 million for children\'s projects since it started in 2005.