LONDON — The good guys dress in black, remember that, with the exception of Darth Vader.

On May 16, Will Smith and Josh Brolin went against the good-guy grain, hitting Leicester Square Odeon’s blue carpet in pale gray tartan and charcoal.

The galaxy-defending duo joined helmer Barry Sonnenfeld to protect London’s citizens against the worst scum in the universe at the gala bow of Sony’s “Men in Black 3.”

The pic’s villainess, Nicole Scherzinger, was in attendance to show the crowds what bad gals dress in — also black, it seems.

Emma Thompson, who plays the new M.I.B. head, had fought for workplace equality, jesting, “I did say, ‘Can’t we call it “People in Black?”?’ and they said, ‘?”P.I.B.?” No. It doesn’t work.’ So it’s stayed ‘Men in Black,’ even though the person who runs the organization is a woman.”

It has been almost four years since Smith last graced the bigscreen, and 15 since the first “M.I.B.” New technology caused the star to fret.

“It’s the first one in 3D,” he noted. “I was concerned my ears might be a problem in 3D, but it turned out to be OK.”