Dr Who?

Joe: Is it really the Tardis Mummy? Is it? Is it really Mum? Mum. Mum
Mum. Is it really the Tardis? Really? Is it though? Is it?.....
Me:YES!! It is!
Joe: Oh its just I peeked in and I saw a toilet so it isn't really the Tardis is it Mummy.. Mum.. Mum. Is it Mum?..
<sigh>