Chelsea have signed teenager Geovany Quenda on a long-term contract through to June 2034.
He has signed an eight-year contract after joining from Sporting CP in a deal that could reportedly be worth as much as £40m (€46.9m).
The clubs agreed the deal in March last year, with Quenda remaining in Lisbon last season, but he has now officially made the move to Stamford Bridge.
"It feels great to be here," he told the club's website. "Chelsea is a great team, and I am excited to play here at Stamford Bridge.
"The club has shown faith in players like me, and I am proud to be here, proud to be part of this club.
Chelsea is delighted to confirm that Geovany Quenda has joined the club from Sporting Lisbon, signing a contract until 2034. pic.twitter.com/NjcJ89Bv9F
— Chelsea FC (@ChelseaFC) July 8, 2026
"I am excited to work with my team-mates and the manager, Xabi Alonso. I'm a very hard-working young person, and I like to help my team.
"I want to be someone known for having the right mentality to help my team-mates and who does their best for the club to win trophies."
The 19-year-old came through Sporting's academy before making his first-team debut in August 2024, becoming the team's youngest-ever scorer at 17 years and 95 days old.
He is also the youngest-ever Portuguese goalscorer in the Champions League after hitting the back of the net in a 4-0 win over Kairat last season.
Quenda made 86 appearances for Sporting in all competitions, netting nine goals, and was also named the Primeira Liga Young Player of the season in 2024-25.
He also helped Sporting to a Primeira Liga and Taca de Portugal double in that campaign, but they missed out on the league title last term, finishing six points behind Porto.
Jesse Derry has also signed a new Chelsea deal which runs through to June 2032, though he is expected to join Sporting on loan for the 2026-27 campaign.