The How I Met Your Mother star and his partner David Burtka, who are parents to 19-month-old twins Gideon and Harper, invited the media mogul to their sprawling estate for the TV chat.
The couple sits in the backyard talking about their decision to have children together, insisting they thought about long and hard before deciding on surrogacy.
The actor reveals, "We really had thought it through financially, emotionally, relationship-wise. We didn't just accidentally get pregnant. These kids come into our world with nothing but love."
The twins were then brought outside by their nanny to meet Winfrey, who gushed over the tots.
Burtka reveals, "They love to swim, they're taking swim classes."
Opening up about the surrogacy, Burtka says, "We knew the surrogate, we didn't know the egg donor, but we saw a video of her and read extensive history on (her) medical (history)", before adding: "Two eggs, two embryos, one of mine, one of his - and two took."
Harris declared, "We lucked out. They're super healthy and happy."
The full interview airs on Oprah's Next Chapter in America on Sunday (03Jun12).