Alan Jackson & Jimmy Buffet had the party theme song on top of the charts in 2003. "It's Five O'clock Somewhere" hit #1 on this day in country music history - and stayed there for for eight weeks. It's our Classic Country Song of the Day.

The song was Jackson's biggest hit - reaching #1 on the country charts and #17 on the Hot 100. Jimmy Buffet hadn't had a top 40 song since the '70's.

Kenny Chesney was given the song before Jackson/Buffet, but did not record it. It went on to be the #3 country song for the decade.

Here's the duo doing it live.

Sing along with your favorite party song with the lyrics below.