'Heroes' Hottie Gets a Ride on Dax Shepard

They haven't officially admitted their romance yet -- but TMZ caught Kristen Bell and "Punk'd" star Dax Shepard looking very cozy on South Beach yesterday in Miami.

Our photog spied Bell and Kate Hudson's leftovers on the beach near the Raleigh Hotel -- where they spent New Year's together -- holding hands as they walked along the sand. Nice birthday for Dax, who turned 32 today.

Bell was later seen sitting on Shepard's lap as they drove around the beach on a golf cart. Fore!