Ouch! Simon Cowell drops not-so-subtle dig at Niall Horan's solo career
The X Factor boss wasn't impressed that Niall signed a solo deal with Capitol Records over his Syco label and said that the Mullingar man would have bagged a number one single if he'd stayed with him.
Speaking about Niall's debut single My Town, which reached number nine in the UK charts and number six in the Irish charts, Simon told the Sunday Mirror: "He probably would have had a number one single if he'd stayed with me.
"But you know who does have a number one this week? James Arthur. Very pleased he's back with us with a fantastic record. Hashtag loyalty."
Niall recently singed a mega-deal with Capitol US, a division of the Universal Music Group, just weeks after Simon predicted that the "loyal" star would join Syco as a solo singer.
A source previously said: "Simon has made no secret of his expectations for Niall to stay loyal to him and has been desperately trying to keep him as a solo act with plans to turn him into a Justin Bieber-style artist.
"They've worked together closely since day one and have always had a strong relationship, but Universal offered him a lot of money. Simon's likely to be frustrated that Niall has gone to a rival."
This follows reports that Simon was angry Niall's former bandmate Zayn Malik for signing on to produce a scripted series called Boys, without consulting him first.
Simon told Entertainment Today: "I think he should have come to me with it, if I'm being honest with you."
However, he added: "Nothing surprises me any more."
Simon helped to create One Direction after the boys auditioned for The X Factor, and signed the band to his label Syco, launching their hugely successful global career.
However most of the band, comprising Harry Styles, Liam Payne, Louis Tomlinson, Horan and Malik, no longer seem interested in their former mentor's help, and have branched out on their own with solo ventures.