Simon Cowell has hit back at LA Reid after he called judging the US X Factor the "worst thing" he's done in his career.

The Epic Records boss lined up alongside the likes of Cowell on the TV talent show, which aired between 2011 and 2013.

However, he told a Midem conference recently that he regretted returning to the show for its second series.

Reid added: "[The first season] a little bit of a vacation. I'd been making music, working at running labels for a long time, and it was a little bit of, 'Let me just have some fun'.

"But the second season, I was fully engaged trying to run a label, and it wasn't fun anymore."

Cowell took to Twitter today (June 9) to send Reid a picture of a tweet he previously posted about Fifth Harmony, who rose to success under the Epic man's guidance.

The Brit added: "If judging X Factor USA was the worst thing you ever did...my taste at times did have its upside.

"I had a great time working with you. We had fun and we got to work together on amazing group. I had a blast. I am getting my own back LA. But you are a friend and you have really worked hard to break the girls."

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