Heidi & Spencer Pratt's Newborn Son Gunner is a Bundle!!!

Get ready ... Heidi and Spencer Pratt's photoshoot of their newborn son is cuteness overload.

Heidi and Spencer decked their son, Gunner, in some of the cutest outfits you'll ever see on a little one. Gunner -- captured by Oxana Alex Photography -- is a cub in one pic while holding a bear in another.

You've been warned ... these pics will seriously give you baby fever.