Only one of those—“TSOP (The Sound of Philadelphia)” by MFSB featuring The Three Degrees—had the distinction of being the first theme song of a television series to be a No. 1 pop hit.

The following are some of the most notable examples in television history of TV shows with iconic theme songs that might not be their original theme songs.

At least, that's what most of us would think...In reality, many theme songs have topped the charts over the years. Find four of them below.

The DJ and producer known as RJD2 found inspiration for his latest music while admiring the complexity of certain TV theme songs. The album is called “Visions Out of Limelight.” ...