The Beatles legend loves to "escape" by writing new lyrics and often finds the best place to explore his ideas is in the bathroom or a cupboard.
"[Songwriting] is a solitary process but that's nice. The rest of the day isn't solitary. I'm doing interviews or taking my girl to school or doing some filming. So I'm with loads of people."
"It's actually quite nice to go into a cupboard, or often bathrooms or toilets which have got good acoustics. So I go in there with a guitar. That's kind of nice. And you escape into a world of your own thoughts."
The Yesterday singer treats songwriting as a job, but enjoys working as he finds it therapeutic.
Asks if he sits down to do a regular day's work writing, he told NME magazine, "Yeah, and it's a nice thing. If you enjoy it, it's a great thing. Get out the way of everyone, get into a little private moment and you can work out your thoughts. It's often therapy I think."
McCarthy doing his first Twitter Q&A:
Paul did his first-ever Twitter live Q&A last Thursday. Haven't read his answers? Just scroll down the timeline! pic.twitter.com/m2bEfMIdTw— Paul McCartney (@PaulMcCartney) October 6, 2013