Danny Gabbidon
Former Wales defender on BBC One

It's going from bad to worse for Wrexham. Aaron Hayden doesn't look happy. Maybe it's a possible calf injury. It'll be interesting to see if he is able to carry on.

Aaron Hayden gets up as though he is going to continue but then sits back down on the turf. Looks like his race is run.

Another reshuffle on the way for the hosts.

Another of Wrexham's first-choice defenders Aaron Hayden is down on the ground. It looks like he may have tweaked his calf.

The problems are mounting for Phil Parkinson and his players.

Stephen Kelly
Former Tottenham defender on BBC Radio 5 Live

It's not even an intricate set-play. It's whipped in towards the near post and McBurnie just gets across his man and he fires the header in.

They'll be kicking themselves at giving away a goal that quickly and that easily this early on.

Max Cleworth, 20, is on for the hosts to replace Jordan Tunnicliffe who hobbles away down the touchline.

More early trouble for the hosts. Defender Jordan Tunnicliffe is down injured and looks to be struggling to continue.

Danny Gabbidon
Former Wales defender on BBC One

It's a dream start for Sheffield United. Exactly the start Paul Heckingbottom will have wanted. From a Wrexham point of view, it's disappointing.

Early corner for the visitors as Luke Young scoops the ball behind.

Stephen Kelly
Former Tottenham defender on BBC Radio 5 Live

It's a huge occasion and this Wrexham team are doing so well in the league, this is just a bonus.

You wouldn't put it past them taking the scalp of Sheffield United.

Here we go. Sheffield United get us under way.

Listen to that roar.

Gary Mixture: Easy to see why Wrexham are flying, after that interview with Ryan Reynolds.

He seems to actually get what it is to be a football fan. When he spoke about the guy's ashes being scattered on the pitch & the ground being a church, it made me well up & think of New Writtle Street.

Right the Racecourse is rocking and the teams are out. Everyone ready?

BBC One

Wrexham co-owner and Hollywood actor Ryan Reynolds, speaking on BBC One:

"The part I find most gratifying is the support from the community outside the club. The fact Wrexham have become a tourist destination for so many folks and they are showing up here.

"There is something special about this town."

Alan Shearer
Former England striker on BBC One

He [Heckingbottom] knows it's a different challenge but you need to keep the form going.

You can feel the atmosphere here, it's electric, so they'll have to face that and it's going to be tough for them.

Sheffield United

Sheffield United boss Paul Heckingbottom on BBC One: "A tough game but the occasion has a different feel to it, like a big one for the round.

"We'll embrace it and try to come away with a positive result.

"We've made changes but that isn't taking away from this competition. It's to protect the players we have and to give others minutes and a great chance to rotate the squad. We've been doing that in the league too, so it's not us taking this game lightly."

Image source, Getty Images

Sheffield United aren't in bad form themselves mind.

The Blades sit second in the Championship and are 12 points clear of third-placed Middlesbrough with a game in hand as they chase promotion back to the Premier League.

With 11 wins from 13 games in all competitions they are bang on form as well. This should be a cracker.

Image source, Getty Images

Wrexham’s Paul Mullin has scored eight goals in his last six appearances in the FA Cup proper and has scored six in three games this season.

The last player to score in the first, second, third and fourth rounds of the FA Cup for a non-league team was Colin Williams in 1984-85 for Telford United.

Chris Sutton
Former Premier League striker

Image source, Rex Features

There is a bit of stardust around Wrexham at the moment because of their famous owners but I don't think there will be a Hollywood ending to this tie.

I am sure they will not go down without a fight in front of the TV cameras, so you could maybe call this game Die Hard - or maybe Dai Hard would be more appropriate for the Welsh side? - but Sheffield United are in great form themselves and should get the job done in the end.

Sutton's prediction: Sheffield United to win after a replay.

BBC One

Image source, Getty Images

More from Ryan Reynolds on BBC One: "In Canada where I am from people are obsessed with this club.

"It's been pretty remarkable. We've sold something like 24,000 jerseys and so many of them went to North America. We can't get them anymore. I can't get one."