By SABC Sport
13th June 2024
The attacking midfielder, 18, has agreed a five-year deal and will finalise his switch to east London when the transfer window officially opens on Friday.
"I'm very happy to be signing with West Ham United, a club that trusted in my work," said Guilherme.
"I also want to thank everyone at West Ham, particularly (technical director) Tim (Steidten) and his team who came to Brazil and not only talked with me, but also with my family.
"They presented the project, and both my family and I liked it. So, I'm very happy to be signing with this club and hope to contribute as much as possible. If things go well, we have a beautiful journey ahead."
Guilherme has won the Serie A title with Palmeiras and been capped by Brazil at under-20 level.
He added: "The Premier League is the best league in the world. I believe I'll improve a lot here with the entire staff at West Ham, which is crucial for my development.
"Growing up, whenever I had the chance, I watched English football. Seeing how it is and now being able to play here is an incredible feeling. Since I was 11, I had this dream, and now it's becoming a reality."