Simon Fraser, 11th Lord Lovat, was a Scottish landowner and head of Clan Fraser of Lovat. Convicted of high treason for his role in the Jacobite rising of 1745, he was the last man in Britain to be executed by beheading. From Wikipedia
The Oscar-winning actor traces his lineage back to Simon Fraser, the 11th Lord Lovat, known for 'laughing his head off' at his execution in 1747.