The Theatre is a large building in Stampy's Lovely World.
Before it was the theatre, it was a mountain, in which Stampy destroyed it to make way for the building. There were parts of the mountain that are still stand today; the hill beside the XP/Resource Farm became Harrison Hill and the huge one on the right became Harriott Hill. In a later video, a house that the Tooth Fairy lives is at a space which was a mountain before.
It took a couple of episodes to finish it, but he makes progress outside the video but some parts of its construction can be seen on-camera. He also visits the Theatre to show the additions of it to the viewers.
It was finished on Episode 41, Completed Theatre.
As you can see the entire building, it is very large! It is likely the second largest building in Stampy's Lovely World.
From the outside, the walls are just made out of smoothstone with the front have redstone lanterns flashing and a counter where you buy tickets. Then on the inside, there is a main lobby made out of birch wood.
Now on the main inside, it is now very grand! As you pass the upper door, it is now a huge theatre with seats. The upper sides are the VIP rooms, where VIP's will watch the show beautifully. The main stage features a black wall, in which it is changed for a show.
The backstage is more colorful, there is a lounge for the actors and actresses, a make-up room and chests to put their stuff in. The lower part is the Music Room, where music is played during the show.