The Carpoolers actor, who became a dad in January this year, said that he knew how demanding twin girls would be because he'd looked after his dogs before.
He joked on TV show Live! With Regis and Kelly: "What's amazing is I had dogs before we had kids and when you get the dog food and you're putting it out, the dogs are like panting 'Food time!' and babies are exactly the same."
O'Connell, who is married to Ugly Betty actress Rebecca Romijn, also revealed that his wife insists on breastfeeding the twins, which sometimes interrupts their quality time together.