The Red Devils are currently preparing to take on the Blues at Wembley on Saturday evening as they bid to try and end the campaign with a trophy.
Manchester United have been in decent form this season and ended up as runners-up to Manchester City in the Premier League table, in what was their highest finish since 2013.
Lukaku is currently bidding to prove his fitness to Jose Mourinho ahead of the final after having missed recent games due to an ankle injury.
The Belgian striker has enjoyed a strong first season at Old Trafford since his move to the club from Everton last summer, scoring 26 goals and making nine assists in all competitions.
And Manchester United legend Irwin believes that Lukaku will be a key player for the Red Devils ahead of FA Cup final showdown.
Speaking to Manchester United’s website, Irwin said: “I’m hoping Romelu Lukaku will be fit.
“We’ve struggled for goals, of late, without him. He’s such a main player for us and such a main goalscorer for us.
“I wouldn’t say we’re over-reliant on him but there are shades of last season when Zlatan Ibrahimovic scored very much the bulk of our goals. It’s been the same again this year. I hope Romelu will score against his former team and win us the cup.”
Manchester United, who have not won the Premier League since 2013, are aiming to make the FA Cup their third major trophy triumph under Mourinho since his appointment at Old Trafford back in May 2016.
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