Not just singing, but writing! We look at popstars who turned author.

It's a feat that only a few acts have managed in the chart's 60-year history.

Who is Sgt Pepper? Which are the album's most popular tracks? 50 years on, The Beatles' eighth album is still a pop cultural landmark.

Does that voice sound familiar? Unknown or uncredited guest appearances on big hits.

We take a look back at who was topping the Official Singles Chart and Official Albums Chart this week in chart history.