The former lovebirds were spotted hanging out together on Friday night at Hotel Griffou in New York's Greenwich Village.
An eyewitness tells me that Miller was in a dining room enjoying a dinner with a gaggle of gal friends when, "at about 11:30 p.m., [Law] walked in with another guy" and joined Miller's posse, the source said.
The two are currently starring on Broadway, with Miller in After Miss Julie and Law headlining Hamlet.
While my source didn't see any canoodling, this isn't the first time Miller, 27, and Law, 36, have been spotted enjoying each other's company recently...
The night before our spy's encounter, they reportedly enjoyed a Thanksgiving-night pizza at restaurant Emporio.
And a week earlier, according to the New York Daily News' Gatecrasher column, they hit the Box nightclub in the wee hours. An eyewitness saw them "get more and more cozy as the night wore on," columnist Amanda Sidman wrote. They stuck around until about 3:30 a.m.
Law's rep has insisted they have not rekindled any sort of romance.
They ended their rocky relationship about three years ago following Law's admission he had an affair with his kids' nanny. Miller has since been tied to Welsh actor Rhys Ifans and Brothers & Sisters star Balthazar Getty.
Check out our Most Dysfunctional Celeb Couples photo gallery to get a glimpse at some other on-again, off-again Hollywood duos we love to follow.