The 51-year-old Clear has been part of Hamilton's technical team for the past two seasons and played a major role in his Drivers' Championship success this year.
However, he will swap Brackley for Maranello with new team principal Maurizio Arrivabene revealing at Fiorano that he will replace Pat Fry as head of engineering.
One person who will not be joining the Ferrari revolution is Bob Bell, who resigned as Mercedes technical director in December 2013.
Arrivabene feels Ferrari now have the right technical staff.
"The team is there," he said. "There is no great news to be announced, no surprises. We have to believe in the people we have." Planet F1
12/20/14 Jock Clear, Hamilton's senior performance engineer at Mercedes AMG Petronas is to move to Ferrari, to become the head of track engineering. Clear will spend most of the next 12 months serving his notice, leaving James Allison to oversee things until then.
12/19/14 This rumor is upgraded to 'fact' with today's news.
12/18/14 Jock Clear, is to leave Mercedes for Ferrari, according to reports in Germany as Ferrari looks to build a super team around Sebastian Vettel.
Clear is currently Lewis Hamilton's performance engineer and was a pivotal influence in the Englishman's charge to the World Championship title this year.
Prior to joining the BAR outfit which morphed into Honda, Brawn and, finally, Mercedes, Clear previously worked at Williams where he was the race engineer and close confidant of Jacques Villeneuve during the French-Canadian's title-winning campaign of 1997.
Ferrari have a multitude of vacancies to fill after the dismissals of Pat Fry, the head of engineering, and chief designer Nikolas Tombazis earlier this week. On Wednesday, the Scuderia also announced that Hirohide Hamashima, in charge of tire performance analysis, will leave at the end of 2014 as new team boss Maurizio Arrivabene clears the decks.
"If Jock Clear leaves Merc to replace Pat Fry at Ferrari that's a very good signing," tweeted Sky F1's Ted Kravitz. "Two drivers titles 17 years apart as engineer, a class act."
Another Mercedes man, Bob Bell, has also been heavily linked with Ferrari. The Silver Arrows announced Bell's departure as Technical Director in April, confirming that Bell would depart at the conclusion of 2014 'with the intention of pursuing new challenges outside the company'. Sky Sports