Danny Schofield struck a dramatic injury-time equaliser to ensure south London bragging rights were shared following a humdinger of a derby clash at The Valley.
Steve Morison's brace after 12 and 24 minutes had put The Lions into a commanding 2-0 lead against a Charlton side unbeaten at home this season.
But referee Mike Jones - he of the infamous 'beachball' incident at Sunderland - handed Charlton a lifeline with not one, but two highly contentious penalties clinically converted by Deon Burton, the second of which also saw Lions midfielder Jimmy Abdou red-carded when he appeared to air-kick the ball rather than make any contact at all.
A spectacular strike from Nicky Bailey gave Charlton a 3-2 lead seconds after the break only for Dave Martin to thump home a 78th-minute equaliser.
Morison then deflected the ball into his own net to hand the home side what looked like being the winner with just six minutes left.
But in a fitting climax to an absorbing game, sub Schofield kept his cool to produce a fine angled finish injury-time to spark wild celebrations amongst the 3,000 Lions fans in the Jimmy Seed stand.
This was never going to be a game for the faint-hearted, especially taking into account the arctic weather conditions.
It was a credit to both teams that they kept their heads in the midst of some truly perplexing officiating that threatend to reduce this match to a frustrating stop-start affair, with the slightest of challenge resulting in the whistle being blown.
Millwall adapted to the ice cold conditions quickly and did their best to warm the visiting fans by roaring into a 2-0 lead.
Morison grabbed his first ever goal away from The Den after 12 minutes, capitalising on hesitancy in the home rearguard to slip inbetween two defenders and calmly steer the ball past Rob Elliot for the opener.
Twelve minutes later The Lions had doubled their advantage. Marc Laird's corner was headed on by Alan Dunne to Andy Frampton, his shot cannoned off the crossbar and there was Morison to sweep home his - and Millwall's second of the game.
Charlton had shown little of a threat up front, and when Frampton slid the ball away from David Mooney after 30 minutes, the Charlton player collapsed in a heap in the penalty area.
To Frampton's disbelief referee Jones remained adamant that contact had been made with the player and although no yellow card was brandished to the Lions man, an unexpected lifeline had been handed to Charlton. Thankyou very much said Burton, who scooped the resulting spot-kick high into the roof of the net to reduce the arrears.
If that penalty decision was soft, the second awarded just eight minutes later was laughable - except for such an important decision to be so horribly wrong was not funny at all.
The ball had pinged around in the danger zone and when Abdou and keeper David Forde seemed to have averted the danger, Lloyd Sam hit the deck. Referee Jones reached for his pocket, one presumed to book the Charlton striker for diving, but to Millwall's horror he showed a straight red card to Abdou who trudged off the field head bowed and in visible distress.
To add insult to injury, Burton stepped up and drilled home his second spot kick of the game to haul Charlton back on level terms.
At the other end appeals following a blatant handball by Jose Semedo from Martin's corner fell on deaf ears as Millwall's 10 men re-grouped and battled on gamely.
But with the second half barely 60 seconds old, Martin and Smith got their wires crossed enabling Sam time and space on the right flank to set-up Bailey, who hit a stunning 25-yard volley that left Forde grasping a thin air.
Charlton were denied a fourth goal soon after when Burton's close range effort clearly crossed at least a foot over the line, yet this time luck was with The Lions as the officials somehow managed to miss this and waved play on.
Spurred on by this piece of goood fortune, back came Millwall and Kenny Jackett's side twice went close; Martin sent a header from Laird's 53rd-minute freekick narrowly over and then dragged an effort wide shortly after following great work by Lewis Grabban and Morison.
Jackett brought on Tony Craig and Schofield with 20 minutes remaining and following a sustained period of Millwall pressure, Martin it third time lucky, lashing the ball home to make it 3-3.
No sooner than getting back on level terms, The Lions found themselves trailing when a Charlton corner hit Morison on the side of the head and went in off the post.
That should have been that for second-placed Charlton, but they didn't count on the incredible resilience and determination of this Millwall outfit.
Ali Fuseini, who worked tirelessly in midfield, was unable to get a clean strike on the ball in the 90th-minute, firing wide after Dunne had created a decent opening.
There was to be no stopping these hungry Lions though, and it was sub Schofield who provided the perfect finish from an acute angle to grab a late, late leveller to stun Charlton and send Lions bench and fans wild.
There was even time for Millwall to carve out an opportunity for a fifth, match-winning goal, but Schofield's rising effort flew over the bar with virtually the last kick of a pulsating clash.
Charlton Athletic: Elliot, Semedo, Bailey, Burton, Basey, Wagstaff (McKenzie, 83mins), S. Sodje, Mooney (A. Sodje, 66mins), Omozusi, Dailly, Sam (Spring, 89mins). Subs not used: Randolph, Llera, Shelvey, McLeod.
Bookings: Burton (16mins), Mooney (45+2mins)
Scorers: Burton (30mins pen, 38mins pen), Bailey (46mins), Morison (84mins og)
Millwall: Forde, Dunne, Smith, Abdou, Robinson, Frampton (Craig, 71mins), Fuseini, Laird (Bolder, 90mins), Grabban (Schofield, 71mins), Morison, Martin. Subs: Sullivan, Ward, Grimes, Price.
Bookings: Martin (16mins), Smith (43mins), Laird (53mins)
Sent off: Abdou (38mins)
Scorers: Morison (12, 26mins), Martin (78mins), Schofield (90+2mins)
Att: 19,105 (away 3,000)