"Two little boys" by Rolf Harris. I heard that song and I want my two boys to feel that way about each other when they are older. Also my DH is in Defence so it just adds a touch of poignancy to it.

I found out from my DH's dad about a year ago that this was the song DH's mum used to sing to him and his brother when they were small. Explains why he always gets tears in his eyes when he hears it as she passed away about 20 years ago.