Justin and Selena Put Your Head on My Shoulder ...

6/20/2014 12:19 PM PDT

Justin Bieber & Selena Gomez Cuddling in the Studio -- PROOF They're Back Together

Justin Bieber caught a few ZZZZZs in the studio last night ... and he did so cuddled all up on Selena Gomez.

This continues the latest reunion of the entity known as Jelena. As TMZ first reported, the two hung out on Monday night at Bootsy Bellows for a friend's birthday ... and Justin recently Instagrammed a photo of them with the caption, "Our love is unconditional."

Our sources say Selena's family is worried about her reconciliation with Bieber and feel it's no coincidence she threw an all-out rager at her house right when she's getting back together with Bieber.

The pic was taken on Shots ... a selfie app.

These two are like Thelma and Louise ... and Justin is definitely Louise.