Rob Kardashian and Blac Chyna Are Engaged!!!

Blac Chyna is one giant step closer to getting jumped in to the krew -- Rob Kardashian popped the question Monday night, and they're engaged to be married.

Blac Chyna was sporting a massive diamond ring as she and Rob went out last night to celebrate. Sources close to the couple tell us Rob asked last night and as expected, she said yes.

Chyna's mom is still in town ... and all 3 hit up Ace of Diamonds strip club to toast their engagement -- which comes after a little over 2 months of dating.

Interestingly, all of Rob's family ... his mom, sisters and brother-in-laws all boarded a plane and flew out of town yesterday for a family vacay.

As Kris Jenner's no doubt saying this morning ... Mazel tov!