Kylie Jenner's Throws Birthday Party for Tyga with His Son and Ass Cupcakes

Kylie Jenner teamed up with the cutest little party planner ever to surprise Tyga for his birthday.

Kylie said King Cairo had been wanting to throw his dad a birthday party, and pulled it off Thursday ... complete with a cake, cupcakes and balloons. The rapper turns 27 on Saturday.

It's a fun clip with Cairo helping dad blow out his candles -- however, we're pretty sure the tyke had nothing to do with the cupcake homage to Kylie's cakes.

Well, we hope not.