A Sean Preston and Jayden James Sighting!

Britney Spears' two sons, Sean Preston and Jayden James Federline, joined their father Kevin Federline's other kids, Kori and Kaleb, on Tuesday.

The occasion? A trip to the L.A. Zoo. Oh boy, oh boy!

The whole gang - Sean Preston, 2, Jayden James, 1, Kori, 5, and Kaleb, 3 - was joined by Federline's mom, Julie, a nanny and one of K-Fed's bodyguards.

Sounds like a fun day ... although Sean Preston and Jayden James look a little terrified in the photo below. Some of those zoo animals are big!

Aww. We see a lot less of Sean Preston and Jayden James than we used to. Y'know, since Britney Spears stopped lugging them on 4 a.m. trips to Starbucks.

When asked if all the kids get along, Shar Jackson recently said, "Oh, yes! They don't know any better â€" they just know they are siblings!"

While Shar denies that she and the FedEx man have resumed boning, she says, "It is important to get along to show your kids that just because you aren't together, you can still be friends and still care about each other."

Less important? Spelling your kids' names right.