Despite being set in the U.S. with American characters, almost all of the actors, crew and production are British.
Near the beginning of the movie, when Mark and Kathy are talking in the morning about Kathy not wanting to start her first day back to work being two hours late because Fran couldn't get there yet and Mark had to go to work, their conversation is done with two camera angles back and forth - facing Mark and facing Kathy. Kathy is holding the baby and standing about 10 feet away from Mark. When the camera is facing Kathy, the baby is sound asleep against her chest, but when it's facing Mark, looking at him from Kathy's angle, the baby's face is just above her left shoulder with his eyes wide open. So as the camera angles change back and forth, the baby is asleep, then awake, then asleep, then awake, etc.