Pegg’s deathly birthday shoot

The star reached the milestone on 14 February (10) but he spent the day filming scenes for the dark comedy, based on the true story of two Scottish murderers who sold corpses to a hospital for research.

And Pegg admits his big day was completely surreal.

He tells Scotland’s Daily Record, “The day I turned 40 I filmed my execution, which was so weird.

“I was standing on the gallows with a noose round my neck being sung Happy Birthday to me by all these peasants, with my friend Bill Bailey about to pull the lever on me.”