Olly Murs is celebrating after selling 1.2 million copies in the United States of his chart topping single Troublemaker.
The Essex pop star said it was a major success for him as a new artist.
He is performing at the BBC Radio 1's Big Weekend in Londonderry in Northern Ireland.
"I just sold 1.2 million from Troublemaker in the USA, that was a big thing for me as a new artist (after) all the success in the UK, to go to America and to sell a single 1.2 million (times)..is a massive achievement for me," he said. He has performed across the US and this month unveiled his new single Dear Darlin.
The Big Weekend is being held at the former Ebrington army barracks in Derry, the first time in the city for around a decade.
Other acts at the final day of the three-day event included Dublin rockers The Script.
Band member Mark Sheehan said he was delighted to be back. He said: "We are so used to it raining that when the sun finally shines we are just waiting for it to rain again, when we think people are going to walk out."
He admitted the band still experienced nerves. He added: "We have got to learn to channel it in a positive way. The day you lose that edge is when you are in trouble."
Sheehan said the vibes in Derry were brilliant and the Big Weekend was a great opportunity to attract massive live acts who usually focus on London. "The amount of money it is generating for the local area, kids out there seeing their first big concert for free, it is incredible."
Girl band Little Mix were among other performers.