Prince Harry saw Prince William's girlfriend, Kate Middleton, as a part of his family.
The Duke of Sussex, in his memoir 'Spare', notes how he loved making his future sister-in-law laugh and wanted his wife to mingle with her one day.
He writes: "I liked seeing Kate laugh. Better yet, I liked making her laugh. And I was quite good at it. My transparently silly side connected with her heavily disguised silly side."
He continues: "Whenever I worried that Kate was going to be the one to take Willy from me, I consoled myself with thoughts of all our future laughing fits together, and I told myself how great everything would be when I had a serious girlfriend who could laugh along with us. Maybe it would be Chelsy"