Walter Matthau & Jack Lemmon—one of the great movie duos of all time. They would become most famously known as the original “Odd Couple”, but these two weren't so different after all, and were actually very much in sync. Their comedy partnership spanned close to four decades, making them one of the longest tenured comedy acts of all time. We take a look at what made them such a durable act and why their partnership was so great.