The 25-year-old, who has played eight Test matches for the Springboks, will join up with the London club ahead of the 2020/21 season to bolster their ball-carrying options in the midfield.
Esterhuizen, who can also play at full-back, recently featured for the Barbarians in their autumn tour, scoring against Fiji at Twickenham Stadium and going on to play against Wales.
Standing at 1.93metres, weighing in at 113kgs and with 72 Super Rugby appearances, Esterhuizen is renowned for his big tackles and ball-carrying impact, picking up the nickname ‘The Giant’.
Regarding his switch to the Premiership, Esterhuizen said: “When the opportunity to play for Harlequins came up, I knew it was the right move for me to develop my career and get the chance to play in the Premiership, as well as experience the European competition, which have always been dreams of mine.
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“Paul Gustard and his team are building something special there and to have the chance to work with a young and dynamic coaching group such as Nick Evans and Sean Long is really exciting. I can’t wait to run out at The Stoop and show them what I can bring to the team.”
Harlequins boss Gustard said: “Andre is an incredible signing for Harlequins. He is a current Springbok who has the ability to change any game through his raw power and strength in the contact areas.
Liam came to watch me for the first time, and it gave the game a whole new meaning! ?? pic.twitter.com/PYXpJItQIT
— André Esterhuizen (@Andre_301207) May 27, 2019
“His physical abilities are impressive enough, but we were further attracted by his capacity to be a second playmaker, distributing before and through the line. He is a fantastic talent and his addition to our squad is very exciting.
“Besides his ability on the field, which is without debate, he is a tremendous human being. He has the character that we want and at 25 is entering his prime as a player.
“He will join a backline that we feel can grow together and develop into an elite unit, developing a deep understanding of each other and building strong friendships.”
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