Kate Beckinsale Blasts Trolls For Claiming She Had Plastic Surgery

Kate Beckinsale's fed up with trolls claiming she's had work done ... firing back in a lengthy Instagram caption and letting people know their bullying's taken a toll.

The actress took to the popular social media site early Sunday morning to address haters who insist she's had a lot of work done over the years ... calling it a subtle, vicious move by bullies.

It's a long rant -- accompanied by a pair of videos featuring the British superstar she says were taken years apart -- but the gist of it ... KB's saying people need to back the hell off and stop spreading lies.

She says people have told her she looks unrecognizable with all her alleged work done -- adding it happens constantly and it's usually women who hit her with the comment.

Beckinsale also goes on a tangent about not worrying about aging because her father died so young ... and says she never thought she'd make it through her 20s fearing she'd have a heart attack as well. She says she had to overcome massive anxiety attacks -- so, age isn't a chief concern of hers.

She ends her statement by asking people to stop bringing up the gossip ... especially since she's dealt with loss. Remember, her stepfather passed away back in January, and many people feared for her mom after Kate posted a pic of her with a bruised eye.

Kate's dealt with many issues this year ... remember, she was hospitalized with a mystery illness back in March -- and, implied last month it was due to stomach issues. She made a return to the public eye just last week at the King's Trust Global Gala.