There's no shortage of cute kids in Hollywood, and little Maddie Aldridge definitely falls into that category!

Jamie Lynn Spears, Britney's 21-year-old sister, just shared this photo of her adorable 4-year-old on Twitter, along with the caption:

"Pool day with my favorite person in the whole world #blessed #momtweet"

Aw, how sweet are these two?

Click "Launch Gallery" above to see more shots of cute celeb kids, including Victoria Beckham's daughter Harper, Jessica Simpson's little girl Maxwell, and Hilary Duff's baby Luca!