"We're very proud of what we're able to do now to really get the full experience of Elvis Presley," Priscilla told ET's Cameron Mathison.
Some of the new additions to the Graceland visitor experience include a showcase of Elvis' favorite motorcycles, a 20,000-square-foot soundstage that will play Elvis movies and concerts and an exhibit featuring some of Elvis' custom-made clothing -- like his famous gold lamé suit. Priscilla told us how the King really felt about that shiny outfit.
"He didn't like the pants, actually," she said. "He didn't like how the pants fit, so after that you would see him wearing black pants with that particular jacket."
Priscilla also revealed that some of the outfits were specifically made to make it easier for Elvis to perform in.
"He would share things with his audience, even his costumes, because he couldn't move in them," Priscilla said. "When he would squat, the pants would rip, or underneath the arm would rip. So Bill Belew designed the jumpsuit, which gave him much more freedom."
There will also be an exhibit presenting some of the late icon's most notable cars, including that famous pink Cadillac.
"He told his mother when he was young -- because she was working very hard, she worked in the hospital... cleaning floors -- he said, 'Mom, I never want you to work on your hands and knees again. When I get famous, I'm going to buy you and Daddy a Cadillac and one for me,'" Priscilla shared.
The most valuable item on display is a guitar valued at $1 million. Part of the reason the instrument is priced so high is that one of the only people to play it, besides Elvis, was Sir Paul McCartney.
Elvis died on Aug. 16, 1977, at age 42.
See more from ET's interview with Priscilla in the video below.