Pupils from Llanelli made history when they treaded the boards in London's West End with a Welsh language production.
A cast of more than 100 pupils will perform at the Strand Theatre
Schoolchildren from Ysgol y Strade staged a one-off performance of the musical Back to the 80s at the Strand Theatre on Sunday night.
It is believed to be the first Welsh medium show staged in the West End.
The show was performed at Swansea's Grand Theatre and was so successful that the school decided to take it to London.
Wynne Owen, one of the teachers who has been involved in the production said: "It was a challenge to move the show from the Grand in Swansea to the Strand in London but we had such a response we though why not.
"It has been quite a challenge practical and financial but we have had such great support from the Welsh societies in London.
"I've been researching in the museum in London and found out that it will be the first Welsh production in the West End - and the first school's production there too."
Teachers wrote to West End impresario Sir Cameron Mackintosh for advice.
Tickets sold well for the show at the 1,067 seat Strand Theatre on Sunday night.
The cast was made up of more than 100 pupils drawn from all years in the school with more students helping out behind the scenes.
Teacher Wynne Owen admitted it was a gamble for the school which had to make sure it covered many of the costs.
But the students who performed said they were excited.
One said: "This is a great opportunity for us. We've had lots of support to carry on an we've been working hard.
"We are going to have so much out of this performance and opportunity.
"And the chance to tell everyone, I've been there."