Ben Affleck is playing chauffeur for the missus on their tropical end-of-year vacay — driving Jennifer Lopez around in a teeny tiny vehicle that he definitely looks too big to be in.

Hubby was behind the wheel Friday in a Mini Moke — which is basically a toy Jeep for adults — while cruising around St. Barts with his wife riding passenger … and like we said, BA seems to be a bit crammed in there, even though Jen’s enjoying the ride.

They were out enjoying the day in the capital of Gustavia … where we’re told they hit up Arawak Cafe for a bite, and later did some shopping at Jacques Zolty (a perfume store) and Bulgari (a jewelry shop) while perusing the town.

Of course, they were shoulder to shoulder for their stroll — with Ben wrapping Jen up tight.

Mega

Earlier in the week, J Lo was spotted out on the beach in a bikini — where her toned body was on display. No sign of Ben there — but the dude was front and center in the streets.

Their kids don’t look to be with ’em for this little getaway … so, a little alone time, it seems.