Just hours after the Duchess of Cambridge gave birth to her son, producers filmed last-minute scenes to slot into the episode.
The new scenes were shot on Monday night and saw Dot Cotton (played by June Brown) discussing the happy news with Abi Branning (Lorna Fitzgerald).
A spokeswoman for the show said: "This is such a momentous occasion for the Royal family, the country and of course the residents of Walford that we felt it should be marked in EastEnders history."
It's not the first time the soap has celebrated historical events. Back in 2011 the square had a knees up to honour the Duke and Duchess of Cambridge's wedding. As well as the street party, footage of the Royal Wedding was also included, just hours after the ceremony had taken place.