If you're gonna thank Jesus for helping you win a Pulitzer prize ... might as well do it at the Vatican ... like Kendrick Lamar.
The rap god hit up the Pope's house in Vatican City with his fiancee, Whitney Alford ... and the SINGLE LARGEST BODYGUARD EVER!!!!
The couple -- along with their entourage -- checked out all sorts of museums and restaurants in the area while blending in with the rest of the tourists.
Seriously, check out the pics ... no mob scenes, no lines for selfies ... just your average world-famous celebrity taking in the sites.
Kendrick's notoriously private and, apart from the Grammy red carpet, he and Alford are rarely spotted in public together.
Fun Fact: Vatican City reportedly has the highest crime rate in the world -- lots of pickpockets.
Good thing Kendrick's got that GIANT HUMAN MONSTER to watch his back!