THE SUN shone and the crowds screamed as top pop acts took to the stage for this year's massive Party in the Park.

Cooper's Field, in Cardiff, was packed with 20,000 screaming fans who had come to watch chart-toppers like McFly, Girls Aloud and Rachel Stevens.

Band of the moment McFly, named after Michael J Fox's character in the Back To The Future films, opened the show with their number one hits, Obviously and Five Colours in Her Hair.

Singer Tom Fletcher said it was amazing to perform in front of thousands.

"We get nervous in front of smaller crowds because you can see each person, but when there are 20,000 in front of you, it's a blur," he said.

Tom said the band were overwhelmed by the speed of their success.

"Everything has happened so quickly for us this year, it's unbelievable. We don't think of ourselves as being huge because it's just something we fell into," he said.

Former Atomic Kitten Liz McLarnon performed some of her new material as well as her former band's favourite, Whole Again.

After Blazin Squad, Irish trio Bellefire and Deepest Blue had warmed the crowd up, Natasha Bedingfield came on and got the fans to join a singalong.

"That was such a fun thing to do," she said. "The crowd was great and I was very excited. So excited I wanted to go crowd surfing."

Straight from surviving Hell's Kitchen, former Bros singer Matt Goss sang some of his new material. The younger fans and former Brosettes appeared to love it.

Matt said later: "I was pleased to hear so many fine Welsh voices.

"It's nice to be out there doing my thing and not worrying about being the new thing."

The biggest cheers of the day were reserved for former Take That heart-throb Mark Owen, Popstars the Rivals winners Girls Aloud, and former S Clubber Rachel Stevens.

Red Dragon FM marketing manager Kath Snell said she was delighted with this year's show.

"We had a fantastic line-up and fans went absolutely mad for their favourite acts," she said.