Kerr, 33, and Spiegel, 26, met at a dinner for Louis Vuitton in Los Angeles and were first linked last year. This past February, Kerr told the Sydney Morning Herald that she and the technology entrepreneur were "really good friends for a long time" before they started dating. However, neither has spoken much about the other in interviews.
"We've just been having fun together and sharing our time amongst friends and family," she said, when asked why they've kept their romance private. "We've been out publicly together a lot but just hadn't been photographed together on the red carpet."
This will be the second marriage for Kerr, who split from her husband of three years, Orlando Bloom, in 2013. She and Bloom have a 5-year-old son, Flynn.