They are getting so big!

Britney Spears celebrated her sons' birthdays on Saturday with a joint skateboard-themed birthday party that looked like any young boys' dream. Sean Preston, who turned 9 on September 14, and Jayden James, who turned 8 on September 12, were all smiles as they posed for a pic at the party for their mom, who shared the happy moment on Instagram.

"Happy Birthday to my two little baby boys," Britney captioned the pic. "They are growing up too fast!!!"

Britney's little sister, Jamie Lynn, unfortunately couldn't be there in person, but did post an adorable picture on her Instagram account of her big sister smiling alongside her sons at the party.

Sean and Jayden's dad, Britney's ex-husband Kevin Federline, also wished his boys a very happy birthday, posting some cute throwback pics of his sons, saying that Preston was "lookin like a skater even when he was 2" and that Sean always wanted to be Spider-Man.

Earlier this summer, the now single pop star brought her boys to Disneyland, where she showed her "two little Mouseketeers" where it all began.