Chas Newby died Tuesday in London. Most people don't know his contribution to the most famous band in the world, so here it goes.

In the early '60s, The Beatles started making a name for themselves in Hamburg, Germany,  and upon their return from their second Hamburg residency, they regularly played at The Cavern Club in Liverpool.

At the time, the group consisted of John Lennon, Paul, Pete Best on drums and Stuart Sutcliffe on bass guitar. Sutcliffe stayed in Hamburg to focus on his art career, so the band needed a bassist.

Enter Chas Newby, who played with John and Paul's prior group, The Quarrymen. The guys asked Chas to step in, and he obliged. This was a critical time in The Beatles' upward trajectory ... they were becoming a thing in both Germany and Liverpool, which ultimately got them a recording contract, and the rest is history.

Chas had other interests -- namely, he wanted to attend university majoring in chemistry -- so he left the band, When he graduated, he took a job at a company that made windshields for trains and airplanes.

For Beatles aficionados who are wondering why they needed a bass player when Paul played bass, at the time Paul played rhythm guitar and piano and after some cajoling when Chas left, he grudgingly played it, and played it brilliantly.

As for Chas, he said he had no regrets about leaving the famous group ... "Music was never going to be a living for me. I wanted to do chemistry," adding, "People sometimes don't believe me when I say I've no regrets, but I really haven't."

Chas was 81.