Henrie told The Insider, via Us Weekly, that both he and his on-screen sister Lyndsy Fonseca were told about the finale when they signed their contracts in 2005.
“We were sitting on set then out of nowhere everyone leaves," Henrie recalled. "They bring in these contracts, Lyndsy and I sign them. Then the show runners go ‘We’re going to tell you how the show ends.’"
“I'm 24 now, but when I turned 21 I started going out with my buddies. Everyone was always asking me ‘Dude, who’s the mom? Who’s the mom?’" he added. "People would try and bribe me with all sorts of alcohol, but I kept silent. I didn't tell anyone. I didn't even tell my mother.”
[WARNING: SPOILERS AHEAD]
HIMYM wrapped Monday after 9 seasons. In the series finale it was revealed that The Mother, played by Cristin Milioti, has died by "present time" and that Josh Radnor's character was just telling the story to his children to introduce them to his one great love: Colbie Smolder's Robin Scherbatsky.