On Monday, he was seen touching down in New York City as he prepared to pressed on with promotional efforts for his newly-released single Sign Of The Times.
But Harry Styles left fans scratching their heads by Tuesday night, when he tweeted - and then quickly deleted - snapshots of Louis Tomlinson, captioned ‘then and now’.
The side-by-side images, which were retweeted by Harry’s account, showed his One Direction bandmate sipping iced beverages in pictures apparently taken years apart.
And as if the point of the post - which was also accompanied by a link - wasn’t confusing enough, it vanished almost as soon as it arrived.
Hordes of followers took screenshots of the fleeting post - and then promptly took to discussing it, with an almost unanimous chorus of fans concluding he was hacked, while other speculated that he may have sent out the tweet in error.
As a scattering of fans popped up to counter both theories, another struck back by writing: 'Do you really think Harry would come out of the blue during SNL rehearsals to tweet a picture of Louis when he never even tweets?’
The 23-year-old heart-throb is currently in the Big Apple, ahead of making an appearance on Saturday Night Live, where he’ll perform his new track.
Harry will be performing Sign Of The Times and another track yet to be revealed on SNL, in an episode presented by comedian and former SNL regular Jimmy Fallon.
The singer - whose band embarked on an extended hiatus in March 2016 - sent social media into meltdown after unveiling his hotly-anticipated debut solo single on Radio 1 last Friday.
One fan enthused: ’@Harry_Styles my baby! I’m super proud of u! That was amazing. I’m feeling like a proud mum love u so so so much! #SignOfTheTimes’.
'Holy s**t @Harry_Styles . Brilliant. #signofthetimes Not what I expected. Loving it. Can’t wait to hear more’, another posted.
Others cooed, @Harry_Styles IM SO PROUD FOR YOU ❤❤❤❤❤❤❤’, 'Harry Styles is the best thing to happen since sliced bread!!!’, and 'my ears have been blessed <33 @Harry_Styles’.
His fellow bandmates Liam Payne and Niall Horan also took to Twitter to congratulate Harry on the track.
New dad Liam wrote on Twitter 'proud of you H. Glad you’re getting to do your own thing’, while Niall added: 'Love it H.’
However, there are concerns that Harry could miss out on the number one spot, as a number of fans could not listen to the single on streaming service Spotify due to a 'glitch’.