Ja Morant knows the perfect way to celebrate a marriage -- the NBA star congratulated a newlywed couple he met at a jewelry store this week with shots of Casamigos!!!
It all went down on Thursday at the famous Icebox store in Atlanta ... which happens to be Ja's go-to spot when it comes to coppin' new bling.
The Memphis Grizzlies guard was doin' just that when a couple pulled up ... and Morant realized they had a lot to celebrate.
You can see in the video ... a staffer introduced Morant to the newlyweds, which resulted in downing some Casamigos.