Hirst doodle makes £18,000.

I guess it should be no surprise that the most expensive living artist has very valuable doodles.

This was proven recently when Damien Hirst did a little ink sketch on a linen napkin from The Ivy restaurant.

It's a depiction of his diamond-encrusted skull, plus a couple of steaming coffee cups in the eye sockets and, of course, the all-important Hirst signature.

He donated the sketch to MacMillan Cancer Relief's "coffee art" auction, where it sold to a private collector for £18,000.