David Beckham underwear sighting in Beverly Hills

Tourists on a Beverly Hills celebrity sightseeing tour got a little more than they bargained for when their bus accidentally rounded a corner and startled soccer star David Beckham scampering around in nothing but his skivvies.

Like a tattooed, less hairy Bigfoot, Becks ducked into the wilds of zip code 90210 when the star-spangled van approached. Some of the surprised passengers were still able snap a few photos of the elusive well-toned figure before he disappeared.

Before anyone starts thinking that Beckham makes it a habit to wander around the tony neighborhood in his khaki-colored undies like some mythical freak, there is a logical explanation.

Beckham, 37, was in the supposedly secluded area of Beverly Hills modeling his H&M underwear line  for a photoshoot when the tourists had their chance meeting.

As the camera-shy Beckham tried to elude the iPhone-ready tourists, he grinned before ducking behind his natural  habitat — some palm trees and a couple of Mercedes.

Seeing the L.A. Galaxy star in his underwear is about as rare as a soccer player taking a flop — check out his Times Square billboard or Super Bowl commercial — but seeing knickers-wearing Beckham prancing around in the wild is a Close Encounter of the Weird Kind.