Designer Cynthia Rowley proves you don't need a big house to make a home fashion statement. The designer showed "Extra" how she turned a one-room Long Island cottage into an adorable Hamptons hide-a-way.

Rowley and her boyfriend, Bill, spend a lot of time at the beach, hanging out at their itsy-bitsy surf shack in Montauk. And upon entering, we couldn't help but wonder: where do they sleep?

Rowley was quick to answer this one: "I know what you're thinking, where do we sleep? Where's the bedroom? Behind this mysterious wall is a little bedroom."

The structure was originally a kit house, built in the 1940's, but today it's filled with flea market finds, like a table Rowley found for only three dollars.

And when the couple's famous neighbors, who include Thom Filicia and Aida Turturro, come by, or guests stay the night, they stay in the garage-turned-guest room. "So this is the guest bungalow," Rowley showed us, adding, "Just don't ever call it a garage."

Ever the designer, Rowley added some basic furniture and a cool sliding door, and voila! -- the perfect guesthouse. "It's all self-contained, and it's got its own refrigerator," Cynthia told us.

A vintage Air Stream trailer on the property also makes a fun retreat for friends, complete with paint-by-number art. Rowley told us it's, "Nothing too fussy or too foo-foo or anything."

When Cynthia isn't kicking back at the beach, she's working on her fashion and design empire. The guru even has a home collection for Target. "For Christmas we're doing edible Christmas tree ornaments," she revealed.

From the runway to her cozy beach hide-a-way, Cynthia Rowley is always making a fashion statement.