There’s no denying that the Prince Harry and Kate are good friends. Not only are they brother and sister in law, but they appear to have the same sense of humour and generally enjoy spending time together along with Kate’s husband, Prince William.

Often described as the ‘big sister he never had’, Kate and Harry have developed a great friendship over the years. Harry has no doubt guided Kate through those first scary years as a member of the royal family. In return, Kate has become one of the most prominent female figures in Harry’s life. The Duchess gives advice to Harry, and he couldn’t wait to introduce her to his girlfriend Meghan Markle!

FIND OUT MORE: What happened when Kate Middleton and Meghan Markle met

Plus they all practically live together! Kate and William live in a four-story Apartment within Kensington Palace’s grounds, while Harry also lives on the premises in the two-bedroom Nottingham Cottage. So not only do they attend royal events together they also spend quality time together at ‘home’ where they no doubt see each other in all sorts of moods and situations!

Prince Harry and Kate laughing

Recently, when Prince Harry gave a groundbreaking interview discussing mental health and his own personal struggles, his supportive sister-in-law had his back all the way!

READ MORE: Brave Prince Harry interview aims to end the stigma on Mental Health

While hosting Team Heads Together runners at Kensington Palace to wish them luck with preparing for the London Marathon, The Duchess of Cambridge was full of praise and admiration for her brave brother-in-law. Talking to one of the runners, Kate called Harry, “brilliant”.

“We all felt there was very much a campaign to get everyone talking and have these conversations, (so) we’ve got to do the same, you know, do the same – so he’s been brilliant,” Kate said.

Scroll down to see the sweet pictures that prove just how close cheeky chappy Harry and kind Kate really are…