Pop superstar Madonna spent her 66th birthday at Pompeii and donated to a local theatre project supporting at-risk kids, the archaeological site said Saturday.

The Material Girl visited the famed UNESCO site Friday night with her entourage, meeting a group of teenagers involved in "Dream of Flying", a theatre project organised by the Pompeii museum that involves local youth in cultural presentations.

"As made known during the meeting, the artist decided to support the project... financing the entire year 2024/2025," wrote the museum in a statement.

Pompeii's director, Gabriel Zuchtriegel, gave Madonna and her group a private tour, after which some of the young actors presented a sampling of their work.

Fans had waited for hours outside the complex's entrance to catch a glimpse of the singer.

Organisers said the project, now in its fourth year and with a budget of about 250,000 euros, has involved about 300 teenagers and children from the area, who take part as actors, musicians and writers.

After a premiere at Pompeii's large theatre this year, the project toured Bologna and Ravenna, with a performance in Vicenza scheduled for the fall.

Next year's play has not yet been chosen, but would likely be a comedy by Aristophanes, Pompeii site organisers said.

The text will be amended by the children "to give voice... to their experiences in a mixture of classicism, contemporaneity and jokes in Neapolitan", the statement said.

The eruption of Mount Vesuvius in 79 AD sent a giant cloud of gases and volcanic ash over the city of Pompeii, burying and preserving its buildings and objects, and even residents itself.