They've had all eyes on the state of their relationship ever since controversially hooking up.

But now 32-year-old TV presenter Caroline Flack has been left heartbroken as her toyboy lover Harry Styles has called their romance off.

The One Direction singer, who will turn 18 on Wednesday, pulled the plug on their burgeoning love affair just days before he jets off for the band's first American tour.

A source tells the Daily Mirror: 'Harry is being realistic about the whole thing.

'He’s going off to America in a couple of days and he wants to be able to commit fully to making the band a success in the States.

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'They’ll be back for the Brits, but all in all they’ll be away for two months. It’s a long time to be apart especially with so much going on.'

Harry and Caroline reportedly split on good terms and the break-up was amicable.

'Harry’s young. He’s just not ready for a long-distance relationship,' the source adds.

'He really likes Caroline and he doesn’t want to hurt her. But he doesn’t want to be tied down.'

Caroline was reportedly given the news earlier this week, just before she was due to co-present ITV2's coverage of the National Television Awards.

And she ensured she looked stunning as she stepped out with her new single status.

The TV star spent five hours in the hairdressers' chair, appearing with shorter, darker locks a few days ago.

The source adds: 'Caroline confided in pals about the split, confirming that it’s over.

'She is upset, but they are still on good terms.'

Caroline put her worries behind her and remained a professional as she co-hosted the NTAs on Wednesday with Matt Edmondson.

Stepping on to the red carpet, she wore a colourful patterned dress with a pink shirt, while her tanned pins were on show.

And she'd clearly had a good time as she let herself loose following her presenting stint.

She tweeted the following morning: 'My.head.hurts.'

Harry and Caroline shocked fans when they initially started dating late last year.

The TV host received a slew of criticism over the 15-year age gap, but she insisted she was doing nothing wrong.

The pair were spotted leaving each other's houses in the early hours of the morning on various occasions, but they were said to have split over the new year.

Although things looked back on track recently, with Caroline meeting Harry's mum.

But it seems for the next two months, at least, the pair will be going their separate ways.