Does Harper Lee prove most artists are one-hit wonders?

Author Harper Lee, who wrote To Kill A Mockingbird, is to publish only her second novel in over 50 years, it was announced this week.

Does that go to show just how difficult it is to have one great idea let alone two?

And how many artists have more than one in the whole of their career?

BBC Arts Correspondent Will Gompertz discusses this in his regular video blog.