Archaeologists have unearthed the remains of William Shakespeare's Curtain Theatre, where his play Henry V was first performed, a spokeswoman for the Museum of London told AFP on Wednesday.
"We have done what's called an evaluation and come across the theatre which is absolutely beautifully preserved, better than any of the others of Shakespeare's theatres," the spokeswoman said.
"It's the last of Shakespeare's theatres to be excavated. It's such a significant site they will make efforts to preserve it in situ."
The theatre, which is referred to as "this wooden O" in Henry V, is being excavated by the museum in east London's trendy Shoreditch area, which in Shakespeare's time was a poor but vibrant district popular with prostitutes.
Part of the playhouse's yard and gallery walls have been found three metres below the ground, with more digging to take place in late 2012 and early 2013.
The Curtain opened in 1577 and was operated by the Renaissance theatre impresario James Burbage.
It was home to the Lord Chamberlain's Men, the theatre company Shakespeare worked with for most of his professional life, and was the main venue for his plays from 1597 until London's famous Globe Theatre opened in 1599.
Romeo and Juliet may also have been first performed at the Curtain.
After the Lord Chamberlain's Men moved to the Globe, other theatre groups continued to perform at the Curtain. It disappeared from the records in 1622, but historians believe it could have remained in use for another 20 years.
"It is inspiring that the Museum of London has unearthed the foundations of the Curtain Theatre," said Michael Boyd, artistic director of the Royal Shakespeare Company.
"I look forward to touching the mud and stone, if not wood, and feeling the presence of that space where Shakespeare's early work, including the histories, made such a lasting impact."
The site's owners, Plough Yard Development, plan to make the theatre central to their redevelopment plans.
"This is one of the most significant Shakespearean discoveries of recent years. Although the Curtain was known to have been in the area, its exact location was a mystery," said a spokesman for the company.
"The quality of the remains found is remarkable and we are looking forward to working with Mola (the Museum of London), the local community and Shakespearean experts to develop plans that will give the public access to the theatre remains as part of a new development."