He hasn't taken a DNA test to prove he's the father -- but Ryan Phillippe is already playing daddy with his soon-to-pop ex-girlfriend ... months after she claimed he left her high and dry with the baby.
According to sources, Ryan and ex-GF Alexis Knapp -- who's due any day now -- stopped for some coffee before hitting up the gynecologist's office in L.A. yesterday ... together.
Knapp insists Ryan is the father -- but the actor refuses to submit to a DNA test until the baby is born ... to prevent any pre-natal complications.
It's the first time the ex-couple has been seen out since Knapp hired a lawyer in March, claiming Ryan saddled her with all the baby's medical expenses -- an allegation Ryan has denied.
At least we know what he did this summer.