Madrid - Barcelona coach Ernesto Valverde has called for unity around Wednesday's Clasico amid fears the world's most famous football match could be marred by Catalan independence protests.
The original fixture at Camp Nou had to be postponed due to riots in October and further demonstrations are expected when Real and Barca play for the La Liga's top spot this week.
"Football has to be for everyone, all over the world," said Valverde in a press conference on Tuesday.
"People should be able to express themselves freely tomorrow, that is what we ask, but that there is respect for everyone. I believe that is the right thing."
Democratic Tsunami, the protest group in favour of Catalan independence, has called publicly for its supporters to gather at the stadium four hours before kick off at 1900 GMT.
"I am not worried about anything," said Real coach Zinedine Zidane.
"I am happy we are about to play a Clasico. It was the same when I was a player, these are the matches you live for, and you are focused only on what happens on the field."
"We are focused on what concerns us," Valverde said. "We are not thinking about what happens off the pitch."
A large-scale safety operation will be deployed around the match involving 3,000 security personnel while both teams have been instructed to travel to the stadium from the same hotel.
For Real, it means staying at a different location to their usual base in the city while Barcelona will arrive at the Camp Nou earlier than normal for their home matches.
"It is a small change, but not very significant. When we play away, we are also in a hotel. it is not a big problem," said Valverde.
"It's something different but the rules are the rules," said Zidane. "They said we have to leave together so we're leaving together."
Barcelona's football club has historically been associated with Catalan nationalism. Catalan banners, flags and chants have been displayed at the majority of home games in recent seasons.
"We are used to it," Valverde said. "We know what is being said but what concerns us most is the game. We have to be professional for 90 minutes, that is what we have to do."
Barcelona and Real sit first and second in the league and level on points, with the Catalans only ahead on goal difference.
Both teams have found form in recent weeks, in part due to the excellent form of their strikers. Real's Karim Benzema has nine goals in his last eight games while Lionel Messi has scored 14 in 12.
"We know we are facing a very good team, we know the player they have in Messi, but we also have our weapons," Zidane said.
"Benzema is having a great season," Valverde added. "He is scoring goals, he is Madrid's top scorer, it is crucial that we restrict him."
Barca will also have enjoyed an extra day's rest before the game after they drew away at Real Sociedad on Saturday afternoon before Real were held by Valencia at the Mestalla on Sunday night.
"It can have an effect," said Valverde. "Four days instead of three, it is a small advantage."
Madrid's Eden Hazard, Marcelo, James Rodriguez, Lucas Vazquez and Marco Asensio will all miss the match through injury. Gareth Bale is fit again but has not started since Real's win over Alaves on November 30.
"Bale is with us, he is training well," Zidane said. "He is an important player and tomorrow, he will be prepared like everyone else."
Valverde said Arthur Melo is unlikely to recover in time from an adductor problem. Ousmane Dembele is out with a hamstring injury.