Lenglet will move to the Catalan club on July 1 after Barca pay his €35m release clause.
According to AS, the defender has told his close-knit team about the move that could see him become a big part of Ernesto Valverde‘s defence next season.
He is expected to sign a five-year contract as Barcelona seek to strengthen their backline, with speculation over the future of Yerry Mina.
However, the 23-year old will be competing for a place in the starting line-up alongside Gerard Pique and Samuel Umtiti.