Do grownups like Justin Bieber?

I am like a huuuuge Justin Bieber fan and I just love him sooooo much. Recently my uncle said he loves Justin Bieber as well and likes to dance to him too. He asked me if I wanted to like have dance party..he said he likes to dance to Justin Bieber in his underwear and told me I should do it too when we get together for our dancing party. I think my uncle is really funy...so I am just not sure if all grown ups like to dance to JB in their undies...because I think it is really funny