Former Brazil and AC Milan goalkeeper Dida praised Alisson for his improvement, hailing the Roma shot-stopper's confidence and bravery.
Alisson has starred for Roma this season, leading to speculation he could leave the Serie A club, with Real Madrid and Liverpool linked.
Dida, a 2002 World Cup winner with Brazil, was delighted to see how the 25-year-old – his former team-mate at Internacional – had developed.
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"Alisson is a great goalkeeper. He is very strong," Dida told Omnisport, speaking courtesy of Hublot.
"He improved so much lately. He is confident and brave. I hope he can perform at his best because he is a great friend of mine.
"I lived with him for two years at Internacional in Porto Alegre. I back him a lot."
Alisson is set to play a key role for Brazil at the World Cup in Russia, where the nation is among the favourites and were drawn with Switzerland, Costa Rica and Serbia in Group E.
Dida hopes Brazil can win a sixth World Cup and first since 2002.
"I hope Brazil will perform well. They were great during the qualifiers," he said.
"Tite changed Brazil's style of play. I hope we can do well and win another World Cup."