Kourtney Kardashian enjoyed some one-on-one time with son Mason Disick, on Tuesday. The pair were coming off an evening of celebrating Kourt's dad Robert Kardashian, at a party honoring the late attorney's birthday.

There was a surprise guest at the dinner, hosting at mom Kris Jenner's house -- no, not Robert Kardashian's ghost ... Scott Disick! Kourt's estranged baby daddy reconnected with the family after his recent ostracization. The supposed rehabbed hard-partyer was recently spotted drinking and enjoying the clubs in NYC during fashion week, according to reports. But now, is he back in the Kardashians' good graces?

Doubtful ... maybe Kourtney was just giving him some time with the kids. Seems like those two are DUNZO!