In a June 2021 interview with Jimmy Kimmel, Harbour revealed that he popped the question to Allen right before the coronavirus pandemic hit the world. "We got engaged right before the pandemic," he said. "And then, you know, the pandemic hit and nothing was happening." The actor did share a humorous story behind his decision to marry Allen, which actually had to do with her two children, whom she had with ex-husband Sam Cooper.
He told Kimmel, "We were riding around the beginning of the pandemic — she has two kids, these beautiful daughters, 8 and 9 — and we were riding bikes out in the country trying to figure out what we were gonna do for the next year or however long it was going to take. And the little one was riding along and she was going like, 'David, Dad, David, Dad.' Because the 'd' got her confused," he noted. "And the older one got very upset with that, which I understand, and was like, 'He's not our dad! He's not our dad!'" To further save Allen's children from "emotional fallout," Harbour reached the conclusion he was going to marry Allen.