Serena Williams' trademark grunt came from her hero-worship of Monica Seles' "cool" court groans

Serena - who is now retired from tennis and is raising her daughters Olympia, six, and 11-month-old Adira, who she has with her 41-year-old husband Alexis Ohanian - said on the 'Hot Ones' YouTube show hosted by Sean Evans: "So I grunt because growing up I liked this tennis player named Monica Seles and she grunts.

"She had this really cool grunt. It was like, '(grunt noise)'.

"And I loved that - I was like, 'That's so cool'. And so I literally would grunt because of her and then it just became natural and then my grunt just became like a (grunt noise.) It was really loud."

She added about the benefits of the noise during play - and other sports: "I guess it's a form of breathing. I grunt playing golf now... it's like a part of my life.

"Other people say it's relieving and exhaling air and it's a different way to exhale air."

Monica landed 59 career titles and played her last professional match in 2003, and her noises during matches were so loud they inspired Wimbledon's Centre Court 'grunt-o-meter'.

She told the Wall Street Journal in 2013 about how she developed the habit in her youth: "Some people loved it, others hated it. I grunted since I was age seven.

"I was a little girl, and they didn't have kid's racquets in those days.

"So my dad just gave me his racquet to play with, but I was tiny, so I put all my energy into it, just the same way I played with two hands from both sides, because I had to.

"It wasn't an issue until I became No1 and then the competitors always try to find a little edge started to complain, because at the end of the day (tennis) was a super competitive industry."