Britney Spears Brings Son Sean Preston, 5, Onstage!

Sean Preston looks right at home onstage!

Britney Spears' adorable 5-year-old son joined the pop star on stage Saturday in Columbus, Ohio during the show's finale. As shown in this YouTube clip, Sean Preston waved to the audience, and his mom, 29, planted a kiss on his cheek.

Sean Preston and his brother Jayden, 4, recently acquired a new half-sibling. The boys' father, Kevin Federline, and his girlfriend Victoria Prince welcomed a baby girl, Jordan Kay, on August 15. Federline also has two children -- Kori, 9, and Kaleb, 7 -- from his previous relationship with Shar Jackson.