Boubacar Kamara, a 22-year-old defensive midfielder, will join Villa on a free transfer when his contract with Marseille expires at the end of this month.
Fabio Carvalho, a 19-year-old Portuguese forward who has just helped Fulham gain promotion to the Premier League, will join Liverpool on July 1.
Carvalho made four appearances for Fulham in the Premier League in the 2020-21 campaign and is set for a back-up role at the Reds, who have brought in attackers Diogo Jota and Luis Diaz over the last two years to provide competition for forwards Sadio Mane, Roberto Firmino and Mohamed Salah.
Kamara was called up to the French national team's senior squad for the first time this month for upcoming Nations League matches.
“I am delighted that we have been able to attract one of the most promising young talents in European football," said Villa manager Steven Gerrard, the Liverpool great who played in the same position as Kamara.
Kamara helped Marseille finish in second place in the French league, so is swapping playing in the Champions League next season for a team that won't even be playing in Europe.
Kamara came through the youth ranks at Marseille and has made more than a century of appearances for the team.