You Might Need to Be Over 40 To Get This Joke: Little Diddy, with Jack and Diane

Source

If you are over 40 you probably got the references immediately and it made you chuckle or groan. 

If not, it is a play on a line from the 1982 hit song for John Couger Mellencamp "Jack and Diane".

Jack Nicholson and Diane Keaton from the 2003 movie "Something's Got To Give" with a miniature of late 90's Rapper/Actor/Producer P. Diddy (Sean Combs).

Here is a link to the video of the song.