AceShowbiz - Kate Beckinsale has fired back at a troll who targeted her new blonde hairstyle. The naturally brunette actress, 50, has altered the colour of her locks for Christmas and showed off her new look in a series of party pictures that showed her in a shimmering dress enjoying time with friends including 42-year-old heiress Paris Hilton.

While droves of fans took to social media to praise her new look, one fan said, "Why such a colour? I thought the original was better - a shame."

The message prompted Kate to hit back, "Because sometimes one fancies a change and is not too bothered about what (you) may think about it, given we clearly do not share the same aesthetic, nor do we know each other."

Referring to a coat he was wearing in his Instagram profile picture, Kate also asked the male fan if he'd like people "saying they don't think your orange puffer jacket flatters you."

She then continued to ask him why it was appropriate for him to remark on someone's appearance, asking him, "Were you brought up to think your unwarranted opinion is the most important factor in any situation ? If so, tell your mum she did a bad job."

Kate's comments won the backing of a flood of Instagram users, who joked about her dislike of the man's jacket.

The actress recently marked her 50th birthday by dressing up and declaring getting older is "great." The "Serendipity" actress reached the milestone age in July, and spent days posting photos of her Playboy and Barbiecore-themed party, which started at her house before she and her friends and family moved on to a club for an impromptu karaoke session.

She captioned one of her string of birthday posts, "I tell you what. Getting old is great. Thank you from the bottom of my heart for the most magical day full of joy and love and dear dear friends and the odd bird (not me but also me)."