"His friends told him to be careful and that it was never going to last, and he feels a little foolish now that it's fallen apart so quickly."
News that the 23-year-old country-pop superstar and the 18-year-old One Direction singer were dating again surfaced late last year.
The Never Ever Getting Back Together singer was spotted hanging out with Styles as she rehearsed for her performance of State of Grace at the American X Factor studio in LA in mid-November.
X Factor co-host Mario Lopez also dished on his radio show that he saw the pair walking off "hand in hand" on the show's set.
The pair first met at the Kids' Choice Awards back in March after being introduced by Justin Bieber. They reportedly dated briefly, before going their separate ways after Styles was snapped smooching with American model Emma Ostilly in Auckland back in April.
Swift and Styles spent Christmas apart, but jetted off to the island of Virgin Gorda, the third-largest of the British Virgin Islands, on New Year's Day to spend some time together.
'I CAN CONFIRM THEY HAVE SPLIT UP'
And that's when, according to the Daily Mail, the proverbial hit the fan.
"Yes I can confirm they have split up," a source told the website.
"They were on holiday and had an almighty row. They are two young stars at the top of their game so who knows what will happen in the future."
"They had a fight," an insider tells Us Weekly. "[Harry] said something he shouldn't have...This [breakup] is definitely going to be for good."
"They are 100 per cent over," chimed another source.
Page Six reports that Swift cut the trip short after a "blowout fight" and flew back to the States on January 4.
Swift looked "glum and introspective" in a snap showing her sitting alone in a boat on her way to the airport, spouted the Mail.
Styles, on the other hand, decided to stick around the neighbourhood to attend a party on Richard Branson's Necker Island, where he hung out in a hot tub and mingled with fans until the early morning hours, according to Business Insider.
"Richard Branson heard Harry was staying nearby so invited him to come check out Necker," a source tells the website. "So when Taylor left for the states, Harry went to Branson's island for the day to let off some steam."
Added the source: "He did plenty of partying and was definitely enjoying himself while hanging out with guests. He returned to Virgin Gorda in the early morning hours looking like he had a raucous night."
Styles headed back to the UK solo on Sunday, and was spotted at Heathrow airport.
Swift was previously dating Robert F. Kennedy, Jr.'s son Conor Kennedy, 18, but the couple called it quits in October.
Her other exes include Joe Jonas, Taylor Lautner, John Mayer and Jake Gyllenhall.
There's been no official word from either of their reps on the split reports.
On Saturday, Swift set tongues wagging when she shared a lyric from her song I Knew You Were Trouble on Twitter, prompting some fans to speculate there was trouble in paradise.
"...'til you put me down," she wrote. The preceding lines go, "Cause I knew you were trouble when you walked in. So shame on me now. You flew me to places I've never been".
Swift opened up about her love philosophy in the December issue of Cosmopolitan magazine, and spilled on what she will not tolerate in a relationship.
"I can't deal with someone wanting to take a relationship backward or needing space or cheating on you," she said.
"It's a conscious thing; it's a common-sense thing. If I was in that situation, if I were them, would I be doing this to me? Would I ever do this to them? If the answer is no, then they're not treating me fairly. I just don't ever want to end up in a relationship that isn't fair ever again."
The chart-topper, whose love life provides endless inspiration for her songs, also told The New York Times Magazine that she once told a boyfriend she wouldn't write a song about him - but she went ahead and did it anyway.
Asked by the mag if her boyfriends ever say "Look, whatever happens, just don't write about me," Swift replied, "The only time that has ever crossed someone's mind was when we were in the process of breaking up."
She added: "Of course I was like, 'Oh, don't worry, I won't'. And then I did.
"Look, it's not like it was written somewhere in the fine print that I write songs about my life. If we break up, I'm going to write about it. But I'm probably also going to write about when I fell in love with you. So there's an upside."
Let the breakup songwriting commence.
Meanwhile, those cheeky One Direction lads have dropped the video for their new single, Kiss You.
Check out the zany action below:
FAST GOSSIP
And finally...
* Mariah Carey says Nicki Minaj posed "unsafe work environment" on American Idol.
* Laurence Fishburne granted restraining order against an ex-con claiming to own his home.
* Heidi Klum overshares about getting "wild and crazy" in bed.
* Snakes on a Plane director David R. Ellis dies at age 60.
* Guillermo Del Toro says he was approached for Disney's new Star Wars trilogy.
* The Spice Girls reunion is apparently OFF, everyone. And the Mirror points the fickle finger of blame at Victoria Beckham.
* Mum claims seeing domestic violence is root of Lindsay Lohan's problems.
* Joan Collins, Stephanie Beacham up for Dynasty revival.
* Nicole Kidman back in character on the Grace Of Monaco set.
* Snapped: Robert Pattinson and Kristen Stewart's hot date in London.
* Second inquest into death of Amy Winehouse confirms singer died of alcohol poisoning.
* Kim Kardashian and Kanye West drop a whopping $11m on Bel Air mansion.
* Listen: David Bowie turns 66 and releases his first song in a decade.
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- Rumour Has It
