EXCLUSIVE

Drake's done more than just financially support his baby mama and her son ... he's pulled out all the stops to be with him almost since birth.

Sources connected to Sophie Brussaux tell TMZ ... Drizzy wasn't present when she gave birth, but he's been actively involved since a paternity test confirmed he's the father. Our Drake sources say no paternity test has been taken yet ... but Sophie has a different story.

We're told Drake met his alleged son, Adonis, shortly after the test and has seen him multiple times.

Our sources say Drake's flown Sophie and Adonis to be with him. We're told Drake chartered a private jet for them on Christmas. Again, Drake has not publicly acknowledged he's the dad.