The 24-year-old spoke to the press following Gremio’s 2-0 win over Internacional on Tuesday.
And he said his move to Europe is down to the final details being sorted.
“Some details are missing, the situation is very advanced,” said Everton. “I just want to thank this club. I was able to honour the shirt.
“I arrived at the age of 16, I won several titles. Thank you for all the care and learning I had here.
“I was not born a Gremista, but it is a club I will love for the rest of my life.”
A meeting between Gremio and Benfica ended on Tuesday without an agreement, Globo Esporte reports.
However, talks are ongoing with an expectation that the Brazil international will soon be flying to Lisbon.
English club Everton FC are offering a similar amount as Benfica, but the winger currently prefers to move to Portugal.