Ariana Grande & Big Sean post their first selfie together as an official couple...

Things are getting quite serious between Ariana Grande and her boyfriend Big Sean.

The couple recently admitted they're dating following several PDA snaps of them kissing/holding hands and now they've posted their first selfie as an official couple (on Ari's Instagram). She captioned it "On our way to grandps' celebration of life earlier." Looks like he's well in with the family. Nice.