"I think I'll just keep it simple and say break a leg, and I know it's going to be amazing," Kutcher said in the video recorded by ET earlier that day. "You have nothing to be nervous about, and you look stunning."
Kunis, who watched the message on the red carpet via tablet, gushed after hearing Kutcher's sweet sentiments.
"I mean, how do you not love him, right?" The 31-year-old actress asked, smiling broadly.