Grint and Groome’s baby news broke when they were spotted out and about in Hampstead, North London, with their newborn bundled in a blanket.
In photos obtained by British tabloid newspaper The Sun online, Grint smiled broadly as he held the baby during a family walk, for which he dressed in all black.
Groome, wearing sunglasses, smiled at the tot and planted a kiss on her forehead.
The Servant actor previously admitted he never stops worrying about his daughter and parenting has made him a “bit of a hypochondriac”.
He told People magazine: “I think becoming a dad forces you to discover things, and now I’m a bit of a hypochondriac. Having a baby, you’re worried about her at all times. Everything seems dangerous.”