The 23-year-old could be at West Ham United until 2022.
But the Irons have moved to make the switch permanent by virtue of his performances, and co-chairman David Gold led the celebrations following the news of his extension.
Lanzini has signed a contract that could see him playing for WHUFC for the next six years. Congratulations Manuel.dg pic.twitter.com/hPKmy01V4C— David Gold (@davidgold) March 24, 2016
Lanzini is gonna develop into such a sick player for us— Fets (@Fazi96) March 24, 2016
Glad to see Lanzini has signed a permanent contract at West Ham. Huge signing for us moving forward in joining Europe's elite. #COYI— Dobz (@Dobz95) March 24, 2016
Lanzini— Adrian Short (@IronMan7WHU) March 24, 2016
Finally confirmed....Great business!!! COYI!!! https://t.co/sTpVypRmXk— West Ham United Fans (@whufcsupporters) March 24, 2016
WEVE GOT MANUEL LANZINI— Ollie (@owiddo96) March 24, 2016
Lanzini confirmed on my birthday not a bad Present from West Ham— bradjackson (@bradjackson243) March 24, 2016
With Lanzini tied up for potentially the next six years, the future looks even brighter for West Ham - a side who continue to defy expectations this season.
Slaven Bilic's side sit fifth in the Premier League table, one point behind Manchester City in the race for Champions League qualification, while they also have an FA Cup quarter-final replay with Manchester United to look forward to.
Winning that competition or finishing in the top four would be a dream way to bookend their stay at Upton Park, where they will leave this summer after 112 years.