Kalulu, 25, has been the most-used outfield player at Juventus this season, making 43 appearances across all competitions and playing every single minute of league action.
He joined from AC Milan for around €17 million in 2024 and has established himself as one of the best signings of the recent era at the club, capable of playing centre-back or right-back under Luciano Spalletti.
His current contract runs until 2029 on a salary of around €2.5 million per year.
The new deal, first reported by the Corriere dello Sport and confirmed by transfer journalist Nicolò Schira, would extend his stay by one year and increase his wages to between €4 million and €4.5 million annually — in line with Manuel Locatelli, Kenan Yildiz and Weston McKennie, all of whom have recently committed their futures to the club.
Sporting CEO Damien Comolli and club legend Giorgio Chiellini had identified Kalulu's renewal as a priority since January.
Manchester United are among the Premier League clubs to have scouted the defender in recent months, adding urgency to Juventus's desire to close the deal quickly.
Kalulu won the Serie A title with Milan in 2021-22 and has scored three goals for the club since arriving in Turin.