Ed Sheeran stunned pupils when he made a surprise appearance during a school concert in Cardiff.

The pop superstar performed for a crowd of 2,000 in the main hall at Fitzalan High School.

“It got me shaking,” said 17-year-old Year 12 pupil Kia, adding: “I had goose bumps.”

The group had been listening to an Only Boys Aloud performance celebrating the school’s excellent performance report when unexpectedly Sheeran took to the stage.

His appearance was part of the launch of the new Ed Sheeran Foundation, which advocates for the teaching of music in schools across the UK.

Sheeran’s Welsh song-writing partner Amy Wadge helped make the event happen in Wales.

“It was so amazing,” Kia said.

“We didn’t know he was coming… everyone was just so shocked.”

Sheeran performed two songs, Thinking Out Loud and Shape of You, followed by a question and answer session with the audience.

Acting headteacher Adam Lear said it happened during a whole school assembly for the 1,800 students and 200 staff.

“He told us he was from Ipswich, small like Cardiff,” said Kia, “and that his teachers were really good to him like ours are and that motivated him to chase his dreams.”

“It was surreal,” said Year 13 music student Maxime, 17, adding: “Here you’ve got Ed Sheeran playing songs you hear on the radio… it changes your school experience really.”

Mr Lear said the surprise happened during a whole school assembly for the 1,800 students and 200 staff.

As Only Boys Aloud performed for the group, behind the scenes 80 music pupil from Year Nine and above were meeting with Sheeran and Wadge before he joined the main show.

“The pupils were absolutely overwhelmed,” he said.

“No one was aware that this was going to be happening, only myself initially.”

“You could see from their faces they were absolutely blown away with what was happening,” said acting headteacher Adam Lear.

Maxime, who plays bass in a Welsh-language band, was among the pupils who met Sheeran privately.

He said they asked him challenging questions, including how Sheeran manages writer’s block.

“He talked about writing some songs he doesn’t like as much at the moment,” he said.

“He was saying you’ve just got to write as much as you can, try and improve and always believe in yourself.”

Paige Cooper, 17, was encouraged to continue in her drama and music studies.

“He was talking about how music as a subject is often looked down upon and how he just hustled from school,” she said.

“It was good to hear because often creative subjects are quite looked down upon.”

She said it taught her the importance of “putting your work out there”.

Another pupil, Katie Brown, 17, said the group was “shocked” when Sheeran walked into the room.

“He gave us an inspirational speech about trying to work hard and no matter how much you fail just keep going,” she said.

When Sheeran took to the stage Katie said the group was cheering and screaming.

“He wasn’t even out of the curtain and everybody had just gone into chaos… what’s Ed Sheeran doing here,” said Paige.

“Then he got his guitar out and everyone was just silent you could hear a pin drop,” Katie remembered.

“He just started singing Thinking Out Loud and it sounded exactly how he sounds on hit recordings,” said Paige.

“Then he did Shape of You he made us join in the chorus and it just felt like we are all and part of it.

“We were singing with Ed Sheeran.”