Gomes, who signed from Valencia on Wednesday for an initial fee of €35m, was strongly linked with a move to Real Madrid.
In an interview following his unveiling at Camp Nou, he said that he decided to joing the current La Liga champions because he felt that the club culture was more aligned with his personality.
The central midfielder is a personal friend of Ronaldo and revealed that the veteran Madrid player was in contact with him following the move.
"I spoke with Cristiano Ronaldo," Gomes told TV3. "He congratulated me and the truth is he was happy for me, but now I will remain a rival of Cristiano, as I was before [at Valencia]. On the pitch there is no friendship.
"I have time with the national team to be with him, and enjoy being with him," the 22-year-old continued. "For the moment what I want most is to enjoy playing with Messi."
His arrival signals the start of what will be an interesting problem for coach Luis Enrique - that of who will occupy the midfield alongside established players like Andres Iniesta and Sergio Busquets.