Credit: ROBYN BECK/AFP/Getty Images

Emma Stone is helping her mom celebrate being cancer-free in an unusual way: they're getting matching wrist tattoos!

"We've never gotten tattoos before and probably never will again," the actress told David Letterman on Thursday. "Two years ago tomorrow she got diagnosed with breast cancer, and she's out of the woods now, which is amazing."

According to Stone, the tattoos will be anything but ordinary -- because they're designed by a former Beatle!

"My mom's favorite song is 'Blackbird' by Paul McCartney, and it's my favorite song as well," she explained. "I wrote a letter to Paul McCartney asking him if he would draw two little bird feet -- because he wrote the song -- and yesterday he sent them to me."

Stone previously met the rock legend, 68, when she visited his house with her Zombieland costar Woody Harrelson.

"We went into Paul McCartney's house and he made us veggie burgers," she recalled. "It was so good. But can you imagine if I was like, 'Well, the burgers were a little [overcooked]?'

Stone admitted she still can't believe the musician came through for her.

"Custom tattoos by Paul McCartney. Isn't that wild?" she said. "He's a good guy."