Jon Hamm has commended his A Young Doctor's Notebook co-star Daniel Radcliffe's work ethic.

The 42-year-old Mad Men star lavished praised on the 24-year-old Harry Potter actor for his commitment to both the film and the West End play The Cripple of Inishmaan.

Speaking to the Los Angeles Times, Hamm said: "We would wrap at 5 o'clock, and he would get in a car, drive to the West End and do a two-hour show. I was, like, 'Dude, how old are you? Because when I was your age, I was not working that hard.' It's impressive. And he is impressive.

"He set a very high bar. I'm used to, when I work on Mad Men, I'm used to working very hard and setting the example. And so I was very pleased that I got to work with this young actor who doesn't have to work this hard, honestly. He can take a few decades off."