Prince George Goes to First Day of Kindergarten, Duchess Kate Too Sick to Attend

Prince George marched into his first day of kindergarten (they call it Primary School) Thursday like a boss -- or like a guy who's mingling with his subjects.

Prince William held lil Geo's hand as they walked into Thomas's Battersea -- a fancy private school near their Kensington Palace home. The likely future King of England displayed impeccable manners, naturally, as he met the headmistress.

Duchess Kate wasn't able to attend because she's stuck at home with severe morning sickness with her third pregnancy.

Today, kindergarten ... tomorrow, all of Great Britain.