Rumer Willis is the best big sister ever!
The 28-year-old took some time out of her busy schedule to hang out with her much younger sibling Mabel — and the pair got together to sing an original song for her Instagram followers.
"I was never this cool when I was 4," she captioned the cute video. "My little sis is my ❤. Mabel I love you so."
Rumer was born almost 14 years before her half-sister, who dad Bruce Willis welcomed in 2012 with wife Emma Heming. Bruce also has daughters Scout, 25 and Talulah, 22, with ex wife Demi Moore, and Evelyn, 2, with Emma.
Too cute! For more celebs with much younger siblings, check out the gallery below!