Prince William has vowed to make sure his children spend time outdoors.

Prince William via Kensington Palace Twitter (c)

Prince William via Kensington Palace Twitter (c)

The 35-year-old royal has Prince George, four, and Princess Charlotte, two, with his wife Duchess Catherine - who is currently pregnant with the couple's third child - and in a speech given at the Fotografiska gallery in Sweden, he praised the country's love of the outdoors and said it was something he wants to instil in his own brood.

He said: "The Swedish love of the outdoors - the way you embrace your climate and environment and are committed to ensuring future generations can do the same; the fact that you do so when it is so cold is really inspiring.

"One lesson that we will take home with us is that children are actively encouraged to spend time outdoors, whatever the weather.

"This is obviously very good for their physical health but, as we learnt this morning at the remarkable Karolinska Institute, it has huge benefits for a child's mental health as well."

During his speech, William also praised the "friendship" between the UK and Sweden, as the Prince made the two-day trip with his wife Catherine, 36, to strengthen ties between the countries in the wake of the UK's decision to leave the European Union.

He continued: "Great things happen when we work together. Indeed this very special place where we are this evening will bring a great new addition to the London arts scene when it opens a sister museum there later this year.

"We have encountered a wonderfully warm welcome. We are particularly grateful for the hospitality of Their Majesties The King and Queen, and of Crown Princess Victoria and Prince Daniel. We have been very fortunate to have spent much of the past two days in their welcoming company, including at their home in Haga. Thank you for making us feel so welcome. We very much hope we will have the opportunity to repay your generosity in the United Kingdom soon.

"Tonight is a celebration of energy, creativity, innovation and engagement in the world - all words we associate with both Britain and Sweden. Above all, tonight is a celebration of friendship. Thank you, all, for joining us."

William and Catherine's two-day trip to Sweden concluded on Wednesday (31.01.18), and the pair will now spend the next two days in Oslo, Norway.