Lana Del Rey’s still deep in that honeymoon haze -- 'cause she hit pause mid-performance not for a water break, but to maul her man with one heck of a kiss.

Yup, it all went down Monday night at Cardiff’s Principality Stadium -- Lana was mid-serenade with "Stars Fell on Alabama" when she suddenly veered off stage ... to lay a full-blown PDA ambush on hubby Jeremy Dufrene.

This wasn’t some cute little peck -- it was a full-on makeout sesh that felt way too private for the side of a stage. Like ... get these two a room, stat!

Lana, looking all blissed out and dazed, floated back to center stage while appearing to wipe away a tear or two -- then casually picked up right where she left off.

Lana and Jeremy tied the knot back in late September at Airboat Tours by Arthur in Des Allemands, LA -- yep, swamp-side vows where Jeremy wrangles gators for a living.