Kaley Cuoco and Zosia Mamet get matching tattoos

Kaley Cuoco and Zosia Mamet have celebrated their friendship with matching tattoos.

The actress took to Instagram on Wednesday to share a series of photos depicting herself and her The Flight Attendant co-star getting some new body art at Arbel Nagar's tattoo studio.

Close-up snaps show that both Kaley and Zosia had the word, "Boop" inked on their inner arms in an italic script.

"I 'booped' you many years ago @zosiamamet . Glad we made it official. Thank you @ar.bel for the perfection," Kaley wrote in the caption.

Zosia posted the same images to her Instagram and added: "It all started with a boop' @kaleycuoco I can't imagine life without you. @ar.bel thank you for this gorgeous permanent reminder. It's perfect."

In response, Kaley and Zosia's The Flight Attendant co-star Cheryl Hines posted, "You guys are cuuuuuttee (sic)."

Last year, the pals also marked the wrap of season one of the drama series by getting paper plane motifs tattooed on their ankles.

Season two of The Flight Attendant is now showing on HBO Max.