Custom House Square might be more used to the slap of skateboards and the roar of buses on a typical Monday evening.

But last night thousands of rock fans had their chance to ‘bring the noise’ to this corner of Belfast city centre for the latest in the ever-growing list of outdoor music festivals which have sprung up in Northern Ireland.

The first night of Belsonic brought dazzling US alt rock gods The Flaming Lips to the city for their only Irish show of 2008.

The festival favourites, who shot to wider recognition with their 1999 album The Soft Bulletin, hit the stage just before 10pm with hit tune Race for the Prize, to the accompaniment of green, white and gold balloons and dancers dressed as superheroes.

Lead singer Wayne Coyne made sure his entrance was one to remember for fans as he burst forth in an inflatable ball.

And there was a nod to their first gig in Northern Ireland when he told the crowd: “Finally we have arrived in Belfast.”

The show saw Custom House Square transformed into a compact, yet bustling 5,000-capacity concert venue.

Revellers gathered from early evening to secure their place at the front of the crowd, and upon opening at 6pm the gates were swiftly thronged with concert-goers.

Among those who had made the journey were Kiri Mitchell and Nikki Stretton from Dromore. The lucky pair managed to avoid the rush for tickets after a relative won theirs through a drinks promotion.

“He got entered into a draw and won two tickets, so it’s been pretty cheap for us,” said Nikki.

Many fans also turned out to see the support acts, which included Belfast duo Oppenheimer as well as indie rock veterans Mogwai and Dublin artist Jape.

Belsonic has been described as Belfast’s main music event this summer, following the cancellation of this year’s Tennents ViTal festival due to the lack of strong headline acts.

“We found a lot of the bands that we contacted really wanted to play Belfast,” said Belsonic organiser Alan Simms.

“The Flaming Lips have wanted to play for a number of years and for whatever reason haven’t made it.

“I think Belfast is about to enter a really golden period for live music. That’s one of the things we wanted to reflect, we wanted to do some of the best local bands that we thought fit the bill.”

Work on constructing the stage began at the weekend, with sound and light systems provided by a number of local companies.

The fun will continue on Thursday night when Coventry band The Enemy hit town with guests Reverend and the Makers, Future of the Left and local acts Fighting with Wire and General Fiasco.

The festival will wrap up on Friday with a headline performance by Liverpool band The Zutons.