According to People, the celebrity jeweller collaborated with the socialite on a handmade, four-carat piece.
"Nicole wanted a beautiful, special ring and wanted to be intimately involved in the design," said Lane.
Over the last month, Richie and Lane poured over options for the design. Lane finished up last week in time for the star's Letterman appearance.
"Nicole was lovely and wonderful to work with on it! We designed it together," he added. "Joel just wanted her to have her dream ring."