To my mind, Peter o'Tooole was a leading man who looked more rock star than actor:
https://www.youtube.com/watch?v=Zm3cKg3HBaA
I don't think a man ever lost his looks so quickly & spectacularly. Here he is 2 years later, playing King Henry II of England, in Beckett:
https://www.youtube.com/watch?v=YGN42AaT3MA
His brain:
https://www.youtube.com/watch?v=pwUxBhi02ZM