Lambert's popularity has soared since his loss to Kris Allen on "American Idol" last May.
Fans will be coming from all over the world to see the sold-out 8 p.m. show at the casino's Special Events Center, said Fantasy Springs spokeswoman Ciara Green.
The casino will host a two-hour pre-concert party for fans, which is also sold out, Green said.
Among the attendees will be an 89-year-old Green Bay, Wisconsin woman known as Lambert's oldest fan.
In a YouTube video, Isabel Paquette told the camera that her family loves Lambert's music. A campaign started online to get Paquette the chance to see Lambert in person.
Fantasy Springs officials heard about the campaign and offered Paquette and her daughter two night's stay at the resort for free, Green said. Lambert's album "For Your Entertainment" hit No. 3 on the Billboard charts and sold around 200,000 copies in its first week.
"Idol" season seven winner David Cook will also perform 8 p.m. Saturday night at the Morongo Casino Resort and Spa in Cabazon.