Hull produced a clinical display at Millwall to win 2-0 in the second leg and reach the Championship play-off final.
After a goalless first leg, the deadlock was finally broken by Mohamed Belloumi midway through the second half at The Den. Substitute Joe Gelhardt then added a second to steer the Tigers to Wembley - with the final on Saturday May 23.
It continues a remarkable campaign for Hull City, who have become the first sixth-placed side in seven years to win their semi-final.
They only stayed up on the final day of last season, and have been under a transfer embargo this term under Sergej Jakirovic.
Having also started the final day of the season outside the play-off places, they are now just one game away from returning to the Premier League for the first time since 2017. They have been down in League One for a season since then as well.
It took until the 64th minute of the second leg for the deadlock to finally be broken. Belloumi was found by Matt Crooks and he cut inside in the box to curl home a brilliant opener.
And 15 minutes later the tie was sealed. This time a clinical counter. Once again Belloumi at the heart of it, as he raced forward before skidding a ball across the box for Gelhardt.
He had just been introduced as a sub, but showed incredible composure to hit a low shot that squirmed through the hands of Anthony Patterson and over the line.
The away end behind the goal erupted. The three home stands left devastated. But on the balance of play, particularly in the second leg, Hull were well worthy of the win.
Hull boss Sergej Jakirovic on Your Site:
"It's an amazing feeling. We were fantastic today. It was a very difficult, demanding game.
"We knew they'd start well, but we responded well and now we're going to Wembley.
"I have had great success as a coach until now, winning championships and everything, but this is maybe number one because of all the problems we had through the season, with so many injuries and, like I said, the embargo.
"This is maybe the best thing that has happened in football in my life."
Millwall boss Alex Neil dismissed the idea that the introduction of Alfie Doughty could have cost them the tie.
The left-back was substituted on for Zak Sturge midway through the second half, and within moments he let Belloumi beat him to score the crucuial first goal.
"What do you do, not bring anybody on?" the Millwall boss said to Your Site when asked whether or not Doughty was up to the speed of the game when he was introduced.
"Do you know what I mean? Your job as a player is to come on, be up to the speed of the game and do your job properly.
"You don't do it the other way, do you? If they come on and score immediately, you don't say, 'Oh well, he wouldn't have been up to the speed of the game.'
"That doesn't come into my thinking. The lads that come on the pitch and the lads that start the game should be fit and ready and available."
Your Site' Andy Hinchcliffe at The Den:
"A lot of observers would have thought, it's Millwall at home, it's obvious they are going to win and get to Wembley.
"But with the way Hull play, it's not about dominating the ball, it's about individuals who can change the course of matches.
"They've done it all season long, that's why they got into the play-offs and that's why they've got through this second leg. They were magnificent tonight.
"They had a bit of a sticky patch in the first half but I just think they controlled the midfield, they were devastating when the subs came on and they thoroughly deserve their day at Wembley.
"Southampton and Middlesbrough will do their homework on Hull, but you've got to be so wary of them. They have shown all season, if you underestimate them or don't plan for the way they play, you will come unstuck."
Curtis Davies on Your Site Football:
"It's Millwall and they are always going to be realistic. If you get a £15-20m offer for Femi Azeez he's going. You have to take it, in my opinion.
"If you want to build with that money, that's fine but, unfortunately, we speak about teams that are already coming down from the Premier League - Wolves and Burnley are coming down and potentially Spurs or West Ham - with big budgets and we don't know where that's going to go. Are Millwall going to be able to compete with them? No.
"This was the best year for everybody. This was the most open year. You're not going to get a Sheffield United that were as bad as this year, Norwich are going to be better next year. All these teams are going to improve.
"It's not an opportunity missed because they could come again, but you're going to need to add that quality because next season people are going to have an eye on Millwall. They are not going to take them for granted."
