That's it from me, I'm off to make sense of it all in a report. Stay on the BBC Sport website for all the reaction.
- Leicester XI: Schmeichel, Simpson, Huth, Morgan, Fuchs, Mahrez, Drinkwater, King, Albrighton, Okazaki, Vardy.
- West Brom XI: Foster, Dawson, McAuley, Olsson, Chester, Sessegnon, Fletcher, Yacob, Gardner, Rondon, Berahino.
And that is it, the end of a breathless, thrilling, wonderful match at the KP. Leicester have to settle for a draw, but goodness knows how they did not find a winner.
Across the face of goal! Leonardo Ulloa is in there, but can't get a touch. It bounces free and that really is it...
Mahrez! Overhead kick, but over the bar. Is that all she wrote?
Two minutes of the 90 left. Home fans in deafening voice, a Leicester free-kick cleared. West Brom looking like hanging on.
Last five. Can Leicester find another late winner, just as they did against Norwich? Wes Morgan! Great block by Ben Foster.
A West Brom change now. Goalscorer Gardner off, James McClean on. Atmosphere still electric, but goalscoring chances thinning.
Final Leicester change. Fuchs departs, Demarai Gray on. Winger for a full-back. Ranieri not sitting back.
Still end-to-end stuff, with West Brom more than holding their own, albeit with some slightly scrappy defending. Craig Gardner from distance, but just over the bar. You feel there's a winner in this.
Jamie Vardy! He is the patron saint of lost causes. Running all night, reaching a ball he has no right to, shooting and forcing a save from Ben Foster. Still so much life in this game.
West Brom should be ahead! Salomon Rondon inside the six-yard box, somehow puts it over. Do not take your eyes off this one.
Great save Ben Foster! The jet-heeled Jamie Vardy somehow catches a loose ball, pulls it back for Jeff Schlupp, whose shot is defelcted. Foster does very well to hang on.
This is interesting. Leicester make a double change, withdrawing Okazaki and the excellent Albrighton. On come Jeff Schlupp and weekend hero Leonardo Ulloa.
Another West Brom free-kick in a dangerous position, cleared to give the Baggies their first corner. They really have been better in this second half.
Albrighton again. Another cross from the left, scrambled behind. It's blood and thunder, breakneck stuff. Superb.
More brilliant action, with Leicester hitting the bar for the second time. Marc Albrighton has had a blinder, and another of his crosses is met by the flying Shinji Okazaki, but the header comes off the top of the bar. This isn't staying 2-2.
West Brom are playing much higher up the pitch in this second half, not inviting pressure, pushing Leicester back. As a result, they are competing much more strongly than they did in the first half.
More breathless action, this time with Jamie Vardy running into the West Brom box, hitting the ground as he's squashed by two defenders. Anywhere else on the pitch, that's a foul...
"Leicester have won the last two matches between these two sides 3-2. Surely it can't happen again?"
Another stunning goal in what has been a stunning match. A needless Riyad Mahrez handball gives Craig Gardner the chance to shoot from dead centre, 25 yards out. The position of the wall and keeper Kasper Schmeichel give Gardner a gaping target, which he finds with precision. Wonderful stuff. What a game.
The Leicester fans are chanting the name of Andy King. He's the only survivor from Leicester's time in League One - he's got winners' medals from that division and the Championship.
"The last two occasions these two sides have met, West Brom have taken the lead, then lost."
The players are back out to more noise. We're back under way...
How do West Brom respond to this? Picking Berahino and Rondon together up front was a bold selection but, apart from the goal, they've had little of the play.
Carlton Fox: Leicester an inspiration to any aspiring team player. Believe in your ability play as a team and anything can be achieved.
Colm: A last minute victory and coming from behind the stuff a champions elect go Leicester.
I'm not sure that this picture does the goal justice, but you can at least see Albrighton's cross to Mahrez, who played the most outrageous flick to King.
Almost seven years ago to the day, Andy King was playing for Leicester. The match was at home, against Stockport, in League One. Barry Hayles came off the bench for the Foxes that night....
Chris Wright: Brilliant finish by King, but what a touch by Mahrez!! Majestic!!
A lone whistle in a cauldron of noise ends the first period. Leicester have come from behind and are flying.
What. A. Goal. Andy King, a one-club man who has been with Leicester through thick and thin, finishes a wonder, wonderful move and gives Leicester the lead. Marc Albrighton's cross-field ball, Riyad Mahrez's outrageous, flying, outside of the heel lay-off, King's clinical finish. Quite brilliant.
Leicester again, yet another attack that is roared on by a tireless crowd. Marc Albrighton down the left, his cross gathered by Ben Foster. West Brom will be looking forward to the breather...
Very, very watchable stuff in front of a raucous crowd. Leicester doing the majority of the attacking, with Riyad Mahrez running at the West Brom defence. This time he delays his shot a little too long and can eventually only shoot over.
I've just seen another replay of the Leicester goal. Olsson wasn't sliding, he just stuck out a boot. West Brom come down the right, but the popular Stephane Sessegnon is crowded out. Leicester defending well...
Off the bar! Jamie Vardy is in at the near post with a header, rattling the woodwork. Leicester are all over West Brom here. Bar the Baggies' goal, the visitors have barely had a kick.
Ben Ashton: You may as well start engraving Leicester's name on the trophy already. Talk about rub of the green! (I'm not bitter, I swear).
Liz Tray: Come on Leicester, you're so close, don't do a Liverpool and bottle it now! The whole nation is with you.
I tell you what, Sessegnon might have had a point. Christian Fuchs put his studs in Sessegnon's shin.
What's happened here? Stephane Sessegnon is having a right old row with the fourth official and has been booked. Mark Clattenburg is having to give him a severe talking to, along with a yellow card. He's very fired up, so much so that he's risking an early night.
"Moments like that really do make you think it might be Leicester's year. It is rocking here."
The equaliser! If Leicester have this sort of fortune for the rest of the season, then the title might be theirs. Danny Drinkwater's shot is going nowhere near, but it takes a deflection off a sliding Jonas Olsson and loops over the helpless Ben Foster. Delirium at the KP.