The 29-year-old, who is currently dating Ashton Kutcher, has been awarded the trophy for the first time ever, reported E! Online.
"Mila Kunis has had a phenomenal year - she's starred in the highest grossing comedy ('Ted') and is the most in-demand Hollywood star right now. Not only is she naturally stunning, but she has a great sense of humour and isn't afraid to poke fun at herself.
"The nation has spoken, and the verdict is that she is officially the perfect girlfriend. She'll take some beating in 2014," said FHM 100 Sexiest Editor Dan Jude.
Former 'Coronation Street' actress, Helen commented, "I'm absolutely thrilled to be voted the Sexiest Woman In the UK. It's a lovely confidence boost, especially when there are so many beautiful girls out there."
Kunis' victory brings to an end a four-year run of British winners. In 2010 Cheryl Cole made history by becoming the first British woman to take the title for two consecutive years, Rosie Huntington-Whiteley won in 2011 and in 2012 Tulisa Contostavlos was number one.