The ex-Barcelona forward thinks that the Ballon d'Or star is has more graft than gift and has tipped Luis Suarez to be a success at Camp Nou
The Camp Nou star was unseated as Ballon d'Or holder earlier this year by the Real Madrid forward, but he starred in the World Cup as Argentina reached the final and won the tournament's Golden Ball for his efforts.
Henry, who played with Messi at Barca before joining New York Red Bulls in 2010, stressed that he rates Ronaldo but just does not think that the Portugal international - or anyone else in the world - can match Messi toe-to-toe for talent.
"Lionel Messi is the best player in the world but I respect the amount of work Cristiano Ronaldo has put into the game," Henry told BBC in a chat with ex-Manchester United defender Rio Ferdinand.
"But Messi is just a freak. It is nice for kids to watch as they can see one guy who was given a gift and the other guy who does it through hard work.
"Louis Saha used to tell me Ronaldo was the hardest worker at Manchester United. I am not saying Messi does not work hard - but it is more natural.
"Ronaldo had to work really hard to reach the top. They have the same mentality but that's the difference."
Arsenal legend Henry also weighed in on the future on Luis Suarez, who has joined Luis Enrique's side this summer for €88 million, and suggested that the Uruguayan would be a massive hit in La Liga.
"He has everything. He's in your face, he's arrogant in a good way, he can volley it, he can score headers," the Frenchman added.
"He has that vicious side to his game - I will not call it cheating. He knows how to score goals. We have seen it against England. They gave him two chances and he scored two goals."