Two strikes from Youri Tielemans either side of an Ivan Toney penalty would ostensibly hand the Red Devils their maiden win on English soil, as the Aston Villa man capitalised on two individual mistakes from the hosts.
However, with the final attack of the game, Bellingham spared England the embarrassment of back-to-back home defeats with a last-gasp leveller, which the hosts' performance - while not flawless - certainly warranted.
Maiden Three Lions starts came the way of Kobbie Mainoo, Toney and Ezri Konsa at Wembley, while Belgium's all-time top scorer Romelu Lukaku returned to the visitors' XI after missing their draw with the Republic of Ireland.
However, Gareth Southgate's defensive plans were thrown into disarray in the 10th minute, as Manchester City's John Stones signalled that he needed to come off, adding to an international injury crisis that Southgate admitted was the worst he had faced in charge of England.
Joe Gomez came on to replace Stones, now also a doubt for Man City's Premier League clash with Arsenal this weekend, but the Liverpool man could only watch on helplessly as the hosts fell behind in the 11th minute to an individual error.
With the ball at his feet outside the box, Jordan Pickford attempted to pick out a teammate in the middle but only cleared as far as Amadou Onana, who poked the ball onto Tielemans with his first touch, and the Aston Villa's man scuffed effort rolled into the bottom corner as Pickford scrambled across his line in the opposite direction.
Pickford's blushes were spared just six minutes later, though, as a neat passing sequence from Mainoo and Bellingham ended with the latter slipping in Toney, who was brought down from behind by Jan Vertonghen inside the area.
Despite the ex-Tottenham Hotspur man's fierce protests, the referee's decision was upheld, and penalty specialist Toney calmly send Matz Sels the wrong way to open his senior England account on his second appearance.
Following Toney's first Three Lions goal, Jarrod Bowen thought that he had also netted his maiden senior international strike in the 27th minute, as Lewis Dunk headed a deep corner back into the six-yard box for the West Ham United man to prod home, but he was clearly offside.
Belgium made full use of that reprieve in the 36th minute, as Dunk failed to intercept Tielemans's cross-field ball to Lukaku, who returned the favour to the ex-Leicester City man with a fabulous outside-of-the-boot cross to an unmanned back stick, where Tielemans arrived to power a header home and restore Belgium's lead.
Barring the defensive blunders, there was a lot to like about England's first-half performance, and Southgate unsurprisingly sent out an unchanged XI for the second half, where Toney rippled the side netting within four minutes.
England's efforts to restore parity for the second time soon cranked up a notch, and Mainoo saw his name up in lights as he connected with Bellingham's cross with a fierce low drive in the 65th minute, but Sels made himself big and denied the teenager.
Mainoo's evening was then brought to an end in the 74th minute as Southgate took him off to a warm reception from the home crowd - rightly so, as the 18-year-old produced an exceptional display on his first start - as James Maddison entered the fray.
The Tottenham Hotspur man was involved straight away in the 79th minute, prodding the ball forward to Bowen, who skipped past a couple of challenges and laid off Phil Foden, but the Manchester City winger's effort flashed across goal and behind.
However, just as Domenico Tedesco's side seemed set to travel home as the victors, a final England attack saw Maddison smartly take the ball down on the byline and pick out Bellingham in space, before La Liga's top scorer expertly rolled the ball into the far corner to send Wembley into raptures in the rain.