It’s official: The Office is getting serious about an Andy-Erin romance. In the March 11 episode, the couple-to-be will finally set out on their first date.

“It’s been a slow process of Andy gaining the courage to ask her out, but he finally does,” reveals Office co-star-slash-showrunner Paul Lieberstein. “The wrinkle in their first data is she gets sick [with the flu], but they attempt to push on anyway.”

The swoon-worthy duo will face an even bigger obstacle in the coming weeks as pieces of Erin’s backstory begin to emerge. “We will reveal that Erin is a foster kid,” says...