Sketchbook➝Famous Faces

I find it really tricky capturing someones likeness in a drawing, so in order to practice I thought I'd try sketching a few famous faces that, if successful, should be recognisable. How well did I do - can you recognise any of the following people?

Who is this Hollywood actor?

How about this American politician?

You'll need a clue for this one, here's a British royal...

...and hopefully easy, this British politician?