*On Sunday, Brandy Norwood will take part in NBC’s single-sponsor primetime programming, which was a popular form of advertising back in the early days of television.

The New York Times is reporting that NBC will show the movie “National Treasure,” and all 35 or so minutes of commercials will be for the TurboTax online tax preparation software from Intuit.

From 8 to 11 ET on Sunday, TurboTax will offer regular ad spots along with special spots, in which three teams compete for a chance to win $50,000 for charity, designed as a reality “show within the show.”

The teams were led by singer Brandy, actress Lisa Rinna and NBC Sports analyst Jeremy Roenick.

Viewers will be able to play along at www.nbc.com/turbotax and can win $25,000 and other prizes.

According to the Times, for the last three years, NBC Universal has created customized ads for TurboTax that feature stars of series on NBC and NBC Uni cable channels such as Bravo, Oxygen and Syfy.

“We’re really taking a risk, owning 30-plus minutes on a Sunday night,” said Seth Greenberg, vp for global media and digital marketing at Intuit in San Diego. “But it’s a risk we decided to take,” because it should “resonate a heck of a lot better than a normal night of commercials.”

“It’s not about buying 30s,” said Tim Spengler, president for North America at Intuit’s media agency Initiative. “What we want to do is break through.”