Staple Singers topped charts 40 years ago

"Let's Do It Again" by the Staple Singers was No. 1 on the Billboard pop chart 40 years ago Wednesday.

Written by Curtis Mayfield, it was used in the 1975 movie of the same name starring Sidney Poitier, Bill Cosby and Jimmie Walker.

The Staple Singers were created by "Pops" Staples and featured his four children. This song was the second and last by the group to top the pop chart.