Listen to Selena Gomez on iHeartRadio | Listen to Justin Bieber on iHeartRadio

(TMZ) - Time to fire up the Justin Bieber/Selena Gomez rumor mill... because Selena was spotted returning home yesterday after hanging out allllll night with the Biebs.

PHOTOS: Justin & Selena - Remember When?

The on-again/off-again (to the infinity power) couple hasn't actually been seen together in some time... and a source tells TMZ this is the first time the two have seen each other in a month.

It's clear these two young lovebirds just don't know how to quit each other.
"Brokeback Mountain" jokes... 'memba those? 

Listen to "Yellow Raincoat" - the song allegedly about Selena from JB's new acoustic album: