A remarkable 600-year-old doorway, potentially leading to legendary English playwright William Shakespeare's dressing room, has been uncovered in the UK's oldest working theatre, according to Euronews.

The archway was discovered at St George’s Guildhall in King’s Lynn, Norfolk, during archaeological investigations sparked by curiosity about a "weird shape" in a wall.

When two noticeboards were taken down, an 18th-century wall was exposed. As bricks from this wall were removed, an even older archway came into view.

Tim FitzHigham, the creative director of St George’s Guildhall, described the discovery behind the plasterboard as “mind-boggling”.

“We’ve got a door that would definitely have been here in the years we think Shakespeare played here and, in all likelihood, was the door to a room where the players changed and stored props,” FitzHigham told The Guardian.

St George’s Guildhall, which hosted its first recorded performances in 1445, predating Shakespeare’s birth, played a vital role in the theatrical scene of the time. The guildhall was a popular venue for touring companies, including Queen Elizabeth’s Men, a troupe established by royal command in 1583, who performed there ten times in the late 1500s.

Recent research by Professor Matthew Woodcock from the University of East Anglia has supported the local belief that Shakespeare performed at the guildhall with the Earl of Pembroke's Men in 1593, during the closure of London theatres due to the plague.

Today, the Grade I-listed guildhall, the largest intact medieval guildhall in England, is the only theatre in England where Shakespeare is known to have performed.