The Duke of Sussex told a mother that he ‘can’t imagine life without baby Archie’ during a visit to Oxford on Tuesday.
Harry, 34, met mum Amy Scullard and her children Emmett, three (who is in remission after being diagnosed with testicular cancer when he was two) and ten-week-old Ida at Oxford Children’s Hospital.
Ms Scullard said: "Harry asked me if she was over the stormy period as babies are supposed be grumpy for the first 10 weeks - and she is.
"He said he's getting used to the baby and how Archie has fitted into family life.
"He said he just feels part of the family and he can't imagine life without his son."
Upon his arrival at the hospital, the new father was also given a locally-made Witney Bear as a gift for baby Archie, by 13-year-old Daisy Wingrove.
He also visited OXSRAD Disability Sports and Leisure Centre, which his mother Princess Diana opened in 1989 and Barton Neighbourhood Centre, Centre, a hub for local residents which houses a doctor’s surgery, food bank, café and youth club.
Harry and Meghan’s son arrived at 05:26, weighing 7lb 3oz, on May 6.
They took part in an intimate photocall two days after his birth at Windsor Castle and later revealed his name to be Archie Harrison Mountbatten-Windsor, following a meeting with the Queen.
The duke broke his paternity leave for a day visit to the Netherlands last Thursday to launch the one-year countdown to the Invictus Games 2020, taking place in The Hague.
He was given a Invictus Games jacket embroidered with the word ‘Daddy’ underneath the logo, as he cycled around the Zuiderpark.
He also opened up to former soldier Dennis van der Stroom, 31, about his late mother Princess Diana during the bike ride.
Mr van der Stroom said: "He [Prince Harry] said missing a mother is like missing some kind of security, how you need that as a son and it falls away when you lose your mother."
Next week Harry will also travel to Rome to take part in the Sentebale Polo Cup.