Paris Hilton posted this image of herself and River Viiperi on Twitter with the caption 'Bye Mumbai! After an amazing trip in India, now taking off to Dubai with @RiverViiperi #JetSetters' (Paris Hilton/Twitter)

Paris Hilton spent her birthday in hospital with her boyfriend after he was injured in a terrifying skiing accident.

The socialite turned 31 on Sunday and celebrated by heading off on a winter vacation at a ski resort in Lake Tahoe, California, with her partner River Viiperi.

However, the holiday ended in disaster when Viiperi fell and cut his leg open. He was taken to a local hospital for treatment, and Hilton stayed by his side.

She documented the drama in a series of pictures posted on her Twitter.com page, adding, "Such a scary day on the slopes today. After seeing the gash on River Viiperi's leg, I almost passed out. I have never seen a cut that deep in my life. He is so brave, I can't even imagine the pain he went through today... After an eventful birthday weekend in Lake Tahoe... Taking off back to LA."

The couple cut the vacation short and travelled back to Los Angeles.

Viiperi later thanked his girlfriend for her support, tweeting, "Back in Lalaland (L.A.) safe & sound thanks to my gorgeous blondie Paris Hilton always taking such good care of me. Love U (sic)... Thank u tweeps 4 (sic) the kind words! 12 days W/ (with) stitches then back 2 (sic) 'almost normal' this sucks but could have been worse. Thankful. Goodnight."