“But I know how I felt when I read with him which was very free, there was something so independent about what he was doing.
“I don’t know, I don’t know how to explain it.
“I literally felt it from the very first time we read through it together, it was like ‘well this is different’”
Leonard Hofstadter star Johnny Galecki also revealed what drew him to the role of the Caltech experimental physicist in the interview.