The 39-year-old former Barcelona full-back was controversially included in head coach Tite's squad for Qatar 2022 amid reports it was to act as a minder for close friend Neymar.
Alves, who now plays in Mexico for UNAM Pumas, will wear the skipper's armband as Tite prepares to make changes, with top spot in Group G guaranteed if they avoid defeat against Cameroon.
Alves, who has recovered from a knee injury to compete at his third World Cup finals, said: "For me it represents the fact that I can wear the Brazil jersey. It makes me very proud to be here.
"I've been with the Brazilian squad for many years and to be able to wrap up this cycle, playing a World Cup, makes me very happy.
"It's been 16 years with the national squad and I've tried to do my very best. Life, I think, always rewards the people who love what they do, who truly do their best in the mission.
"I think I'm reaping what I have planted over those 16 years."
Tite, expected to choose either Juventus' Danilo or Real Madrid's Eder Militao ahead of Alves at right-back in the tournament's latter stages, insisted he was not yet focused on a last-16 clash with either Ghana, Portugal or South Korea.
"We have 26 great players and I do not have time to be focusing on the broader picture," Tite said.
"We are busy working, preparing our players. I have a little time to have dinner with my family after matches and the work goes on.
"We are fully focused on preparing for the next match. We have a clear objective.
"We have played two matches with two different teams and now we play the third match with a completely different team.
"We'll make a few changes, we'll include keys players. In two games we used 19 players. We do not call them starting players or reserves. They are all players."
Cameroon, who threw themselves a lifeline when hitting back from 3-1 down in their second group game against Serbia to draw 3-3, must win and hope Switzerland fail to beat Serbia, but even victory over five-time World Cup winners Brazil may not be enough for the Africans.
Head coach Rigobert Song said: "With regards to what is at stake tomorrow, we know the Brazilian squad off by heart.
"But we aren't worrying about what they're going to bring to the game, it's about what we bring to the game.
"Yes, they have already qualified for the next round. That's a luxury we haven't got, however we can't worry about what they're going to throw at us.
"We know they're a very strong team, but if we think about that and concentrate on them - are they going to shake up their squad? Are they going to rotate positions?
"I don't really care about what they're going to do, it's about us. We are preparing as if we're playing a final."