The Argentina international became the west London side’s second signing of the January transfer window after swapping Milan for London.
Chelsea FC had to reach an agreement with the 31-year-old’s parent club Juventus before his switch to Stamford Bridge could be finalised.
Sarri worked with Higuain for two seasons at Napoli and the Argentine striker scored 36 goals in 35 games in the 2015-16 Serie A season.
The World Cup runner up experienced one Serie A campaign under Sarri before Higuain completed a move to Juventus in the 2016 summer transfer window.
The Italian manager will be hoping that Higuain can add more firepower to his Chelsea FC team as the Blues look to secure a top-four finish.
Higuain – who watched the Blues claim a penalty shootout win over Tottenham in the League Cup semi-final on Thursday night – is confident that he can help Chelsea FC to achieve their goals under Sarri’s management.
“It was a wonderful season [under Sarri at Napoli] and one in which I broke the goal-scoring record, which is very important out there,” Higuain told Chelsea FC’s website.
“It was a fantastic year for myself and Maurizio, and a period which we shared together, even though it was a short time.
“Now I’m just happy to be working with him again at a big club like Chelsea which has all the history and wonderful team-mates.
“I think everything is set on the right path to achieve our goals by the end of the season.”
The South American forward arrives at Stamford Bridge with a wealth of experience following spells at Real Madrid, Napoli, Juventus and AC Milan.
Higuain admitted that Sarri managed to a get understanding of the Argentina international during their brief time together at Napoli.
“Maurizio Sarri is the coach who, in my career, has got the best out of me as a player,” Higuain added.
“He’s someone who knew how to work with me, particularly on the emotional side. That year together was fantastic and in big parts thanks to him, so coming to work with him is very important for me.
“I’m really happy to have been given the opportunity to do that and I want to get back to that level.”
Chelsea FC are in fourth place in the Premier League table and three points ahead of Arsenal and Manchester United.
The Blues agreed a deal to sign Christian Pulisic earlier this month before loaning the American back to Borussia Dortmund for the remainder of the season.
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