The 21-year-old has already appeared in Team Sky colours as a stagiaire, racing both the Giro del Piemonte and Japan Cup in 2015.
"It's super exciting for me", said the rider. "This season was about getting another year stronger, becoming more consistent, and developing as a rider and as a person, before making the big step up from a Continental team to a WorldTour team."
He reiterated just how excited he was about the move, adding: "I’m 21 now, so I think this is the ideal time to be stepping up into a big team. I’m super, super excited."
As a 14-year-old Geoghegan Hart attended Team Sky's launch event, and has been on their radar almost as long.
“We’ve been following Tao for a long time now and obviously had him with us as a stagiaire at the end of last year," said Team Principal Sir Dave Brailsford.
"He’s continued to show real progress this season and we’re delighted he’ll be taking the next steps in his career with Team Sky.
“Tao is another exciting addition to the group of young, talented British riders we have at Team Sky.”
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