The pint-sized warbler has revealed how the One Direction heartthrob just happened to be in the same recording studio as her when she was working on her second studio album 'My Everything', and offered to pen a song for her.
She explained: ''I was at the studio one day and he was there, and literally, [songwriters] Johan [Carlsson] and Savan [Kotecha] were like, 'Hey, do you want to write something for Ariana?' And he was like, 'Sure, mate.' And he just did.''
It seems the 21-year-old pop diva was impressed with Harry's song-writing efforts as the track, 'A Little Bit of Your Heart', will feature on Ariana's second studio effort, released on August 25.
Appearing on a one-off special of MTV's 'TRL' called 'Total Ariana Live', she gushed: ''It's a beautiful song. He's an amazing writer. It's really beautiful. He's amazingly talented.''
Harry, 20, has been flexing his musical muscles more and more by writing songs for other artists of late.
One Direction will release a new album of their own later this year.
This Doctor won't be saying 'goodbye' in the same way as those who have left the series in recent years.