Mark Ballas -- I Got a New Zip Code in My Step ... 90210

'DWTS' star Mark Ballas just dropped $2.5 mil on a fixer upper.

It will make more sense when we tell you this ... the house is in a primo section of Bev Hills. It's a skosh over 4,600 feet, with 5 bed and 5 bath, but it needs major work.

We're told Mark hasn't decided whether he'll live in it or flip it, but he has options, and talent. Mark and pal Derek Hough flipped a house they bought together for $1.2 mil, plunked $200k into it and sold it for $1.8 million. The renovation was featured on "Mark & Derek's Excellent Flip."