Katy Perry has congratulated One Direction's Niall Horan on his band's US iTunes chart Number One success.
Katy, who originally auditioned Horan for The X Factor, tweeted: "@NiallOfficial congratulations, you didn't let me down! xo." Back then she warned him "likeableness isn't going to sell records, it's talent. And you have…a seed of it", before putting him through to bootcamp.
The 1D frontman replied: "Thank you for putting me thru!we've been working hard,I won't let you down."
Perry wasn't the only one forwarding on her good wishes, Justin Bieber also tweeted Niall to say: "good guys always win bro. congrats."
'Up All Night (Deluxe Edition)' and 'Up All Night' are at Number One and Number 2 respectively on the US iTunes album chart.