Niall Horan wants Kardashian curves

Niall Horan hopes to have an "a**e like Kim Kardashian" after working out.

A video of the Irish singer and his One Direction bandmates undergoing a vigorous exercise session was aired as part of their seven-hour streaming event, 1D Day, over the weekend.

Showing off his goofy side in the clip, Niall puts on an American accent to tell viewers what he gets up to in the gym.

"Welcome to my workout DVD, I'll be with you for the next 45 minutes to give you the lowdown on how I stay in shape," he smiled.

Niall is then seen performing squats and hopping up and down steps, which he believes will give him a voluptuous bottom like the reality TV star.

"I've done 8,000 squats today... I'm going to have an a**e on me like Kim Kardashian," he mused.

Fellow heartthrob Harry Styles went shirtless for the candid video, showing off his various tattoos and muscley physique.

After being shot working out with a trainer the 19-year-old star opened up about his fitness regime.

"It's currently 12.15am. I train for an hour, then go to sleep for four hours," he explained. "Get up again at 5am, have breakfast and go to Bikram yoga and have an espresso afterwards. Easy peasy!"

When holding a weighty barbell Harry laughed: "I'm training to be Thor."

The video was shot during the Australian and New Zealand leg of their Take Me Home world tour earlier this year.

Bandmate Liam Payne clarified why he and the boys have to be in such good shape during their epic performances.

"Being out there jumping around like a lunatic each night, and we're 126 shows in now, it's quite crazy," he commented. "So staying fit is a huge deal. We've got the stadium tour next year and there's a 100-metre catwalk that we're going to have to run down so we have to keep in shape otherwise we just won't be on it."

While fellow group member Louis Tomlinson appeared to be absent in the video Zayn Malik was filmed throwing punches.

"We've been training pretty much every day on the Australia and New Zealand tour," he added.

1D Day was staged to thank the group's loyal fans for their support.