They also met other cast members, including Steve McFadden (Phil Mitchell), June Brown (Dot Cotton), Jack Ryder (Jamie Mitchell) and James Alexandrou (Martin Fowler).
The Queen then went to the Blue Peter studios and met old and new presenters.
Presenter Simon Thomas gave her a gold Blue Peter badge, and the Queen said: "How splendid!"
He then made the Queen laugh by saying she could now get into all the London attractions for free.
Afterwards, Simon said he was relieved the Queen had laughed so he didn't look too silly.