The How I Met Your Mother star has been serving as TV personality Kelly Ripa's co-host for the past week (begs28Nov11) while producers try to fill TV veteran Regis Philbin's recently vacated spot.
However, when his one-year-old tots came down with a cold - just hours before his planned TV appearance - Harris decided to bring little Harper and Gideon to the studio so he could keep a close eye on them.
Opening the show, he said, "Our babies are backstage. Not for a photo op (opportunity). Because they're not doing so well...
"Our daughter just decided, while playing with one of those tabletop electronic devices that sings songs... just to vomit all over it... And then about 10 minutes later, again. And then, like, two minutes after that, again... It's like The Exorcist baby. I feel so bad for her. I think she has a stomach bug."
And the actor's son Gideon isn't doing much better.
He added, "He's got a little rash. He's very needy. If you let him down, he cries and wants to go back up (and be held) again. It's very cute."