Actually, no, but they are basically adjacent to each other. Tiananmen Square is located to the south of the Forbidden City, across Chang’an Street. There is no overline bridge or zebra crossing connecting these two places. You have to walk through the underground passages on both sides of the Square to cross the street.
However, although the square is on the south side of the street, the Tiananmen Tower is on the north side, right next to the Forbidden City. You can regard it as the entrance of the city.
Because of their proximity, most tourists put them together to optimize the itinerary when planning their trips. They would first watch the Flag-Raising Ceremony in the early morning, walk around the square thereafter, and then start their tour in the Forbidden City.
Other interesting facts about Tiananmen Square