Neymar was seen visiting the Real Madrid dressing room after Barcelona's 3-2 pre-season victory against their rivals on Saturday, Planeta Deportiva have reported.
The Brazilian forward reportedly spoke with compatriots Casemiro and Marcelo for 15 minutes, further fuelling speculation that he is set to leave the club this summer.
What Neymar and his international teammates discussed in the Real Madrid dressing room is not clear, although it appears that a move to Paris Saint-Germain is growing increasingly likely.
The 25-year-old is reportedly waiting until his father receives a €26m loyalty bonus from Barcelona on Monday before finalising a deal with the Ligue 1 club.
Neymar's transfer to PSG is now expected to be formalised next week for a world record €222m fee.
The former Santos man was seen storming out of training on Thursday after an altercation with teammate Nelson Semedo.
The two players had to be held back after the fracas and Neymar angrily departed the pitch, throwing his bib to the floor and kicking out at a ball.
Despite the incessant speculation surrounding Neymar and reports of his imminent exit, Barcelona president Josep Maria Bartomeu has insisted that the club have no intention of selling, although admitted the decision ultimately lies with the player.
"Neymar is one of our best players and we do not want to lose him," Bartomeu said.
"We want him to continue with us, he still has four years left, but the players decide if they want to go so there's nothing more to say."