Rob Kardashian and Blac Chyna: Our Engagement Is Poppin'!!

Rob Kardashian and Blac Chyna found a fringe benefit to getting engaged -- cheat day with the ice cream man!

Rob and Chyna turned their Range Rover around when they saw an ice cream truck parked on the side of the road. You'll recall they also made an In N' Out run last month to celebrate Rob's birthday.

As cheat days go, this ain't so bad -- they scored two bomb pops at about 40 calories each -- but still ... there's a pattern here.

The day after the wedding should be epic!