Whoa! Selena's out and blonde babe is in!

Justin Bieber usually goes for brunettes, but he found a tall blonde he liked Tuesday night at the Roxy where he was attending the Craig David concert. The young hottie looked like she was dressed in PJs, wearing pink sweats with heart patches on the knee, fuzzy pink slipper slides and a long black cardigan sweater. Biebs was his usually streatwear self in white, with his shaggy hair flowing from underneath his cap.

Here's how it went down ... Justin arrived with pals to the Sunset Blvd. venue and around 1am, he left with all his boys AND with this new lady in tow. Yes, she left in his black SUV, as you can see in our pix. Where were they headed? His crib, folks. Looks like her PJs probably came in handy for a little sleepover!

Meanwhile, Selena's in Australia and she's been snapped on a yacht in Sydney harbor with a cute dude from Hillsong Church. Maybe that prompted Justin to get a little revenge???

UPDATE - Bieb's babe has been ID'd as Alabama-born model Baskin Champion (interesting name). And yeah, she's a Sports Illustrated swimsuit model, of course.

Check out this video of the two inside the Roxy, jamming (and grinding) ...