Duchess Catherine and Prince William were in Ireland visiting a range of different organisations, including a local police station and arts centre, when she was quizzed on baby #4.

Catherine wore a powder blue $3240 Mulberry coat and Jenny Packham dress for her day out, and paired the look with navy blue sued pumps and a matching blue suede clutch.

While chatting to waiting fans outside the the Braid Arts Centre in Ballymena, northern Ireland, Kate met Alan Barr and his adorable five-month-old baby James.

The Duchess spotted the cute duo in the crowd and told Alan: “He’s a very sweet little boy… He’s so diddy. Makes me very broody.”

Broody has a similar meaning to the word clucky, referring to the strong desire to have a baby.

When asked by Alan is she was planning for baby number, Catherine laughed and joked: “I think William might be slightly worried.”

One of the stops on Catherine and William’s northern Ireland tour was a visit to Sure Start, a program that supports parents with children aged four years old living in disadvantaged areas.

The royal couple reportedly spoke about their own parenting experiences, particularly with sleep deprivation.

One of the mums in attendance, Kathryn Ward, said Catherine and William said despite having staff available, they prefer to get up in the night if any of their children wake.

“They were chatting a bit about sleep deprivation,” Kathryn told the media after the Royal visit.

“Even though they get the help that they have, they’re still parents as well and want to get up with their own children,” she said.

“So they understand the stresses and pressures we’re going through, even though they got a couple of people more hands-on. They’re fantastic. Really on our level.”

(Text: Lauren Sullivan, bauersyndication.com.au / Additional reporting: Natalya Molok)