Why is my Audi engine making a clicking noise?

I recently noticed that my Audi's engine has been making a strange clicking noise. It's most noticeable when I start the car and it seems to go away as the car warms up. What could be causing this and should I be concerned?

This could be a sign of a worn engine component, such as a faulty valve or lifter. It's important to have this checked out by a mechanic as soon as possible to prevent any further damage.