The Beatles producer George Martin signed the legendary rock band in its early days more for its four members' endearing personalities than for their music, he once revealed in a video posted on Twitter Wednesday by his son.

George Martin, who died in March 2016, helped propel the group to global success in the 1960s and was dubbed "the fifth Beatle".

"There were four of them, and I said 'who are they? What are they?'" the legendary producer told his granddaughter, in the video released by his son Giles Martin, also a producer.

Les Beatles en concert en juillet 1965 à Londres
Les Beatles en concert en juillet 1965 à Londres C.PRESS via AFP

George Martin had met The Beatles in London as the band members from Liverpool were searching to establish themselves -- before they became the world's most famous foursome.

"When I listened to what they did, it was ok but it wasn't brilliant," he recalled in the filmed exchange.

"But the magic bit came when I started to get to know them, because they were terribly good people to know," he continued.

George Martin and his son Giles pictured in 2011
George Martin and his son Giles pictured in 2011 GETTY IMAGES NORTH AMERICA via AFP / Ethan Miller

"They were funny, they were very clever, they said all lovely things, they were the kind of people that you liked to be with," George Martin detailed in the old clip.

"So I thought 'well, if I feel this way about them, other people will feel this way about them, so therefore they should be fairly popular.'"

Born in 1926 in north London, George Martin, the son of a carpenter, was seen as playing a pivotal role in getting The Beatles off the ground.

He remained a key influence on the band over the ensuing years, from their first "Please Please Me" album through to "Abbey Road".

Only the group's last album, "Let it be" in 1970, was produced someone else, in that case Phil Spector.

George Martin was knighted in 1996