The actress stunned her followers today by posting what looked like an X-rated text conversation.
However, Kate Beckinsale soon revealed that it was all a hoax.
The 45-year-old had been trying to trick her friend with a close-up picture of her armpit, hoping to convince her it was a photo of something way more rude.
Unfortunately, her pal was too quick-witted and soon fired back with an equally suggestive snap.
A disappointed Kate replied: “I was so hoping you’d think I was sexting you by accident.”
The bombshell brunette captioned the screenshots: “Turns out you have to get up awfully early in the morning to fool another woman with the old unsolicited armpit vagina game.”
Her 2.7million Instagram followers were charmed by her cracking sense of humour, and let her know in their comments.
One wrote: “You are the coolest woman of all time.”
While another gushed: “You are hysterical.”
The Underworld star has been making headlines the past few months after she started dating comedian Pete Davidson.
After their 20-year age gap received media attention, Pete silenced the trolls with a quippy sketch on Saturday Night Live.
The pair were first seen together in January, and were caught on camera sharing a smooch at an ice hockey game a few weeks later.