Why is my Audi A5 making a strange noise when I turn it on?

I recently noticed that my Audi A5 is making a strange noise when I turn it on. It almost sounds like a knocking or rattling sound. Is this something I should be worried about and should I take it to a mechanic?

Yes, it is definitely worth taking your Audi A5 to a mechanic to get it checked out. Strange noises are usually a sign of an underlying issue and it's always better to address it sooner rather than later.