The 22 huge and muscular NFL players stood and watched with their hands on hips looking at each other as if a UFO had just landed in the middle of the field.
It was something out of the ordinary, something indescribable, something ugly.
To the rest of the British crowd they were watching a tradition seen at some of the great sporting occasions including the Ashes, Wimbledon and a multitude of football matches.
The streaker, a man in his mid-thirties wearing nothing but a pair of blue jeans, ran onto the pitch and got to the half way line unchallenged with his arms in the air. But seemingly surprised by the lack of police chasing him, proceeded to greet several of the American visitors, includuing Corey Graham, with a "high-five".
After a minute someone from the staff of the Chicago Bears decided to do something. Wearing a suit and tie, he chased the imposter to the corner, but then, missed the tackle to bring him down.
Another six or so people began the chase, all seemingly from the Bears operational staff. Fortunately for the streaker, there weren't any pros in the hunt. As he ran once again towards the middle of the pitch, he was tacked midflow by two men, which looked a "hard hit" according to one spectator, and the police were called.
It certainly gave the crowd something to laugh about. As for the players, they seemed less amused.