The actress, 50, posted a selfie to her 5.6 million Instagram followers with the caption: “Happy Monday.”
The next slide was a bit more provocative, however, and read: “You aren't very lady-like are you?
“Me: Suck my n*t sack mother f***er.”
Some fans wrote in the comments how they felt about the post. One said: “Oh come on Kate. The second post was distasteful. Be a little mature.”
To which Pearl Harbor star Beckinsale replied: “If you are mature I def don’t want anything to do with it.”
Another wrote: “What happen to that sweet girl from pearl harbor.” Beckinsale replied: “She got ig.”
It comes after the star - who this year lost her beloved cat Clive - spoke out about the constant trolling she receives on social media.
On Sunday, she said while she is trolled - often by “tw*tty men” - she continues to post through the negativity in hope that there remains a “possibility of it [social media] being such a loving and positive force”.
To make her point, Beckinsale shared a short clip from an appearance she made on The Tonight Show Starring Jimmy Fallon.
She told how after being on the show – which saw her tell a story about her fake sneeze – a mother of an autistic seven-year old said his first ever word.
Beckinsale wrote in the accompanying caption: “So – those of you who have been following my stories the last couple of days have definitely had a little insight into the fairly constant f**kwittery and bullying that I can receive pretty regularly on this app.
“What I want to say is first of all, I have been overwhelmed by the number of supportive and incredible messages I have received from kind strangers that outnumber and outweigh the a**eholes by two million percent .
“The second is this, and the reason I feel social media has the possibility of being such a loving and positive force – a few years ago I went on Fallon and told this story about my fake sneeze.
“I received a DM a week or so later (which sadly got lost) from a woman who said her autistic 7 year old son had been entirely non verbal forever, and then became obsessed with this sneezing clip, kept requesting it over and over, and then suddenly said the first word he has ever said in his life and the word was ‘Achoo.’”
She added: “May I thank all of you and most particularly that lady who I wish would message me again so I can thank her properly.
“She and you are why I stay on here and why I feel people are ultimately good and the chance to connect with strangers can be such an incredible gift.
“Unless you are a farty t**tty man who thinks women should stay in the kitchen or some other irritant in which case it’s a gift in the sense of a poo wrapped in some sweating cling film. Love you, you the good ones, you the achoo-ing ones xxx.”
She was also recently forced to deny claims by trolls that she had had cosmetic surgery after posting a picture of herself with an ice pack around her head after getting a wisdom tooth removed.