Billie Lourd Honors Late Mom Carrie Fisher's Birthday With Touching Tom Petty Cover

Carrie Fisher & Billie Lourd, 2015
Albert L. Ortega/Getty Images

Carrie Fisher and daughter Billie Lourd arrive for the Premiere Of Walt Disney Pictures And Lucasfilm's 'Star Wars: The Force Awakens' held on Dec. 14, 2015 in Hollywood, Calif. 

Monday (Oct. 21) would have been Carrie Fisher’s 63rd birthday, and her daughter Billie Lourd knew just how to mark the occasion. She posted a video on Instagram of her singing Tom Petty’s “American Girl” because it was “one of her favorite songs,” according to Lourd’s caption.

Sitting atop Fisher’s bathtub -- “one of her favorite places,” her daughter noted -- Lourd belts out the sweet tune for her late mother, who died at age 60 in 2016 from a heart attack.

She kicks off her caption with a uniquely spelled-out “Happy Birthday Momby” message, serving as a direct tribute to Fisher’s idiosyncratic way of tweeting that substitutes letters for obscure emojis.

“Today would have been my Momby’s 63rd birthday. Not that I’m some kind of grief expert by any means, but on milestones (or whatever you want to call them) like this, I like to celebrate her by doing things that she loved to do,” she wrote for the caption. “I’ll probably have a pint of vanilla Haagen-Dazs and a Coca-Cola for dinner.”

Watch Lourd’s heartfelt tribute below.