Not even 30 years could come between Brooke Shields and her Calvins.

On the Sept. 22 episode of "The Ellen DeGeneres Show," the 45-year-old model turned actress revealed she's still able to slip into the same pair of jeans she sported at age 15 in her controversial Calvin Klein Jeans ad.

"They didn't look pretty," she admitted, "but they fit."

The racy 1980 ad opens with the young Shields whistling "My Darling Clementine" before suggestively declaring, "You want to know what comes between me and my Calvins? Nothing."

Shields told DeGeneres, "That was one of the first times they had sort of smart and provocative television commercials," adding that the promo was originally intended to be played in movie theaters.

The actress's mom, Teri, kept the two pairs of jeans used for the ad, and the star recently donated one pair to the Met for a fashion retrospective. "The other ones," she said, "I tried to pour myself [into]." And? "I got those suckers zipped up!"

Brooke Shields Calvin Klein jeans ad

Brooke Shields in her controversial 1980 Calvin Klein Jeans ad. Photo: Calvin Klein / Courtesy NPC

Of course, mother-of-two Shields confessed, she didn't quite look perfect in the pants.

"They came up to here!" she said, motioning under her chest. "They were so high. I looked like a sausage in them, but I was going to get them zipped up if it was the last thing I did, so I could say that I fit into them!"

In other news, check out Jessica Simpson's new jeans line.