Celebrities love to play the real estate game, so ET looked into who's buying and who's selling the hottest properties in town.

It's been a transition period for Justin Bieber, who has a new glass house to go along with his new blond hair.

PIC: Bieber Goes Blond!

The property, located in Beverly Hills, is somewhat of a landmark and the Biebs is renting it for roughly $60K a month.

While Bieber's 7,500-sq. ft. home came ready to go, Reese Witherspoon is working on a fixer-upper. She just bought a historic home in Nashville for just under $2 million.

"It's a project that's going to take me a while," Reese said of restoring the home. "It's something I'm going to do little by little. It's a passion project for me."

On the selling side are stars like former Baywatch star David Charvet, who has turned into a salesman in the real estate game.

David is a high-end home builder with his own company, Joan's Builders Group. He and wife Brooke Burke-Charvet are selling their mansion for $13 million.

"Celebrities can make a lot of money out of real estate," said David Parnes of Million Dollar Listing Los Angeles. "I know that Ellen DeGeneres recently purchased a house and then Sean Parker came and bought that house from her for a lot more money. I think it really does influence the price. People want to buy a celebrity house -- celebrities want to buy a celebrity house."

But even the celeb real estate market can take a hit from time to time. Michael Douglas and Catherine Zeta-Jones' Bedford, N.Y, estate sold for under the $8.1 million asking price, going for $7.5 million.

Faye Dunaway's West Hollywood duplex also took a price drop, going from $1.75 million to $1.55 million.