Ashlee Simpson celebrated her 30th birthday with a Christmas-themed party yesterday (03.10.14).

The singer marked her annual milestone with a winter inspired bash at her home in California with her close friends and new husband Evan Ross.

A source told E! News: ''One of Ashlee's best friends threw her a 'Dirty Thirty' Christmas-themed party at Ashlee's place last night.

''They had real snow brought in. Ashlee wore a coat and played in the snow.

''They have huge candy canes all over, Christmas trees, colourful lights draped around.''

Evan - the son of legendary singer Diana Ross - took to his Instagram account after the party to post a picture of his gorgeous wife and her friends sitting in the artificial snow, next to a blow up snowman.

He wrote alongside the snap: ''Last night made it @ashleesimpsonofficial favorite holiday Christmas in California. It was a snowy one. Harry birthday baby. (sic).''

It is not known whether her sister Jessica joined in the celebrations but the blonde beauty did take the time to wish her sibling a happy birthday on Instagram.

She said: ''Happy Birthday Ashlee! There is no one I believe in more than you. Thank you for inspiring me everyday. I love you!!! #dirty30. (sic).''