A laugh will do you good.
4 seconds sound clip from the A King in New York (1957) movie soundboard.
You can hear this line at 01:04:56 in the Blu-ray version of the movie.
Quote context
[...]
- I can't pronounce my P's or my M's. It's terrible.
- Stop thinking about yourself!
- There are two comedians on next. They're very funny.
- I'm in no mood for anything funny.
- The doctor said I'm not to laugh. I might split something.
- What?
[...]