Let us know, external which Premier League players could get in these sides.

Angus Rodger: Silva, Hazard, Aguero, Matic, Fabregas... list goes on

Danny Dawson: Lloris

Sajana Mandula: De Gea and Courtois can walk right into Barca and Madrid's 1st teams at the moment.

Alex Regueiro: In Barca's? Probably Zabaleta or Seamus Coleman at RB. No others.

Spanish football writer Andy West at the Nou Camp

"No surprises in the starting XIs. The only question mark was whether Barca midfielder Sergio Busquets would be risked after a quicker than expected recovery from an ankle injury, but Luis Enrique has not taken the gamble. Javier Mascherano's extra physical power and directness might be a better option against Real Madrid in any case.

"Lots of British fans will have a particularly keen eye on Gareth Bale, and something to keep an eye on is how much defending he is asked to do by Carlo Ancelotti.

"Real right-back Dani Carvajal will not want to be left one on one against Neymar, so Bale - like Isco with Lionel Messi on the other side - will have to track back as well as launching counter-attacks. Busy night for those two."

Could any Premier League players get into these sides?

Mustafa Hussain: De Gea for Casillas, Aguero for Benzema, Terry for Pepe..

Reece Davies: I think Hazard would get into both of their teams.

Dean Pannell: Both Zabaleta and Ivanovic. Both lack a good RB. GK spot easily taken by De Gea, Courtois or Lloris too

How have the two main men fared in 2015 so far? Like chalk and cheese. Some good chalk, admittedly.

Cristiano Ronaldo's tally of nine goals in 14 games since the turn of the year is good, very good, but Lionel Messi has racked up 20 in 18 appearances.

All of this since moving out to the right as well. He is playing on a different level at the moment, he led Manchester City on a merry dance in midweek and now he will set his sights on putting Real to the sword.

Not many of you seem to rate Neymar. I wonder if the Brazilian can prove a point tonight?

Could any Premier League players get into these sides?

Davey T: If Gareth Bale can play for Real Madrid, then there are several who could also

Luca Young: Hazard, Fabregas, Azpi, Terry, Rooney, Sanchez, Kane and Eriksen

Luke Smith: Costa over Benzema, Hazard over Neymar, Courtois over both keepers

Real Madrid make two changes from their last league game as Iker Casillas comes back in in goal, and World Cup winning metronome Toni Kroos starts in midfield. Gareth Bale is in.

Real XI: Casillas, Carvajal, Pepe, Ramos, Marcelo; Kroos, Modric, Isco; Bale, Ronaldo, Benzema

Spanish football writer Andy West at the Nou Camp

"To illustrate the global interest in tonight's game, accreditation has been supplied to more than 800 members of the media, representing 164 organisations from 35 different countries, coming from as far afield as Burkina Faso, Hungary, Chile, the United Kingdom and… erm… Spain."

Could any Premier League players get into these sides?

Shaun, Glasgow: Hazard, Ivanovic, Azpilicueta, De Gea, Aguero would get in Real's team. Courtois, Terry, Matic would get in Barca's. Ratio of 13-9 in La Liga's favour.

James, Stafford: Hazard or Silva replace Neymar and Aguero replace Benzema

Martyn, Reading: Courtois would get in either team, So would De Gea, Costa for Benzema? Kane in a season or two?

Barcelona make just one change form the team which toyed with Manchester City. Claudio Bravo returns in goal.

Barca: Bravo, Pique, Rakitic, Iniesta, Suarez, Messi, Neymar, Mascherano, Alba, Alves, Mathieu.

Image source, Getty Images

The biggest game in world football?

Plenty will argue that it's not even the biggest game of the day, with Liverpool v Manchester United pretty high on the global audience scale.

Estimates place the TV audience for this one at 500 million people. Half a billion. That's roughly everyone in the United States and everyone in Nigeria all tuning in at once.

Or everyone in Vietnam, the Philippines, Germany, France, Saudi Arabia, Argentina, Italy and Peru.

Eden Hazard was the first name on my mental list - but I'm not so sure he would get a start. Squad player.

Could any Premier League players get into these sides?

Shohan Sen, Kent: Alexis Sanchez at Barcel... oh wait! How about Mesut Ozil at Real Madr... oh wait..

Sam, London: Eden Hazard would replace Isco at the moment in that Madrid team.

Don't let Andy West hear you say that (see 18:44)!

Wesley Sneijder had a full head of hair the last time Real Madrid won both league games over Barcelona. Can Carlo Ancelotti's side upset the apple cart and pull it off tonight?

Joe: Ronaldo is and has been better than Messi, just, but neither of them are the best ever plenty better!

Spanish football writer Andy West at the Nou Camp

Image source, EPA

"Cristiano Ronaldo has scored 41 goals in all competitions this season - so is it possible that he is under the weather?

"Most players would dream of such a run of form but the great one has hit just five goals in his last 10 league outings, having failed to register even a single shot on target in four of them.

"And with his goalscoring troubles providing the spark, Ronaldo now seems to be in a spiral of negativity where anything and everything is capable of annoying him.

"Real's notoriously demanding fans, for example, have clearly got under his skin with their recent complaints about the team's poor performances. During the latter stages of the 4-3 home defeat by Schalke in the Champions League, he responded to fans' jeers by darkly muttering to Karim Benzema: "How shameful, how shameful."

Read more on Ronaldo's woes from Andy West here.

Image source, Reuters

When you look for weaknesses in either of these two sides you come up with a pretty short list.

But which players from the Premier League could make it into the Barcelona or Real Madrid starting XIs? And why would they get in? Who are they replacing?

I'm thinking both goalkeepers could be replaced, a full-back or two, maybe a centre-back, give Harry Kane a few years...

Let me know what you think.

Get in touch at #bbceurofooty,, external pop on to the BBC MOTD Facebook page, external or BBC Sport's Google+ area., external

You can also text us on 81111 in the UK only - don't forget to say who you are and where you are texting from.

Adrian Bennett: Barcelona are going to get spanked tonight by Real Madrid

Danny Dawson: Messi is without question the best player of all time.

Ishtiaq Ahmad: Decider of the liga.

Have your say over on Facebook., external

Spanish football writer Andy West

"Doesn't look like a near 100,000 venue from outside, does it? Explained by the fact that the pitch is sunken, so you enter the stadium halfway up."

It's much like Molineux then?