The owners of homes renovated by HGTV's "Fixer Upper" couple Chip and Joanna Gaines have found a gold mine in renting out their homes to fans.

The Waco Tribune-Herald reports that several of the homes that the couple have worked on are being offered as vacation rentals on sites like Airbnb and VRBO (Vacation Rentals By Owner).

They have been so popular among fans of the show that at least one homeowner has bought another home in order to rent out the "Fixer Upper" house full time.

But the Gaineses, who have spent a lot of time and effort building their brand, aren't so eager to see others cash in.

Their spokesman, Brock Murphy, told the Tribune-Herald that for Season 5 of their hit show the couple might require stricter contracts for participants.

"We want to honor our national viewing audience. We want to do remodels for clients' homes. That's the true intent of our show, and we want to ensure that does not get lost in this new vacation rental trend," Murphy said in a statement.

The couple have spent 12 years renovating homes in and around Waco. They were rocketed to fame in 2014, when HGTV put them on the air.

Now they have several projects going in the city, including their flagship Magnolia Market at the Silos and The Bakery at the Silos. They recently bought the Elite Cafe in Waco, but haven't said what their plans are. There is also a magazine in the works.

And the couple have their own vacation rental called Magnolia House. It rents for $1,295 a night, and is booked through 2016.

Some of the homes listed on the vacation rental sites play up their "Fixer Upper" connection to a large degree.

Some property owners said they didn't necessarily anticipate renting out the homes before their "Fixer Upper" experience, but living in the houses became a nuisance with fans continually stopping by and taking pictures.