Wrexham suffered a cruel FA Cup plot twist as the non-league club run by movie stars conceded two stoppage-time goals in a 3-1 defeat at Sheffield United on Tuesday.

Owned by Hollywood actors Ryan Reynolds and Rob McElhenney since 2020, Wrexham had become the headline act in this year's FA Cup.

They defeated second-tier Coventry in the third round and took Championship promotion chasers United down to the wire before finally bowing out in a fourth-round replay at Bramall Lane.

Anel Ahmedhodzic put United ahead but Wrexham equalised through Paul Mullin's penalty to spark dreams of another against-the-odds result straight from the pages of a blockbuster movie script.

Mullin then missed a penalty that would have given Wrexham the lead and Billy Sharp and Sander Berge played the villains with goals deep into stoppage time to earn United a fifth-round tie against Tottenham.

Despite the lack of a Hollywood ending, Reynolds, unable to attend the match, saluted his fifth-tier team in a tweet immediately after the final whistle.

"So proud of these boys. And the 4,000 plus away supporters who gave it all," he wrote.

Second in the National League, three points behind Notts County with two games in hand, Wrexham's main ambition this campaign is securing a return to fourth tier for the first time since 2008.

But the FA Cup has always been an enjoyable diversion for the north Wales club, who famously knocked out Arsenal and West Ham in previous years.

Only a stoppage-time United equaliser had denied Wrexham when they drew 3-3 in January and Phil Parkinson's side acquitted themselves well again.

"Obviously we are disappointed we haven't gone through but seeing how the Sheffield United players and staff celebrated at full time is a mark of how we pushed them," Parkinson said.

"There are so many positives for us to take into the second half of the season."

United took the lead in the 50th minute as Ahmedhodzic exchanged passes with James McAtee before sweeping into the roof of the net from a tight angle inside the six-yard box.

Wrexham drew level in controversial fashion after 58 minutes when a tug on Mullin was ruled a penalty even though replays showed the offence took place just outside the area.

Mullin smashed in the spot-kick in front of 4,000 jubilant Wrexham fans for his 29th goal this season.

If Wrexham's first penalty was dubious, there was no doubt about their second in the 72nd minute when Oliver Norwood's rash lunge on Mullin sent the striker crashing to the turf.

But this time Mullin fluffed his lines from the spot as Wales goalkeeper Adam Davies plunged to his right to make the save.

Sharp made Mullin pay for that miss as he cleverly worked space to slot home from 12 yards in the fourth minute of stoppage-time.

With Wrexham stretched in search of an equaliser, Berge clipped in their third goal in the final seconds.

"I could not be more proud of those men than I am right now. They gave it absolutely everything," McElhenney tweeted.

Sharp was less enamoured with the Wrexham story, adding: "I wasn't happy with a few of their players.

"The way they were as a club, eyeing up Spurs. They had not even beaten us. I've got a smile on my face now."

Elsewhere in Tuesday's fourth-round replay action, League Two side Grimsby earned a trip to Premier League strugglers Southampton.

The Mariners' surprise 3-0 win against Luton, who sit fourth in the Championship, moved them into the last 16 for the first time since 1996.

Championship leaders Burnley needed a stoppage-time winner from Nathan Tella -- his second goal of the game -- to seal a 2-1 victory against third-tier Ipswich at Turf Moor.

Burnley's fifth-round opponents are third-tier Fleetwood, who won 1-0 against League One leaders Sheffield Wednesday. (AFP)