And rather than it being based on something Cheryl had said or done, Lily has claimed it was actually born out of sexual frustration, as she had yet to achieve orgasm.
We did tell you it was unexpected.
In her new autobiography, which has been previewed in the Guardian, she wrote: “Sorry Cheryl, I was angry because I hadn’t come yet.”
Lily explained that at the time, she believed Cheryl’s band, Girls Aloud, were “colluding with the oppressors” with their skimpy stage outfits.
“I was jealous. I was frustrated,” she said. “I was struggling with my own issues around sexuality. I’d never even had an orgasm.
“And then here were these gorgeous girls – my peers, colleagues so to speak, and co-workers – taking their clothes off with wild abandon and being loved and rewarded for it.”
The pair’s feud started in 2006 when Lily featured a B-side named ‘Cheryl Tweedy’ on her debut single ‘Smile’.
The song’s lyrics discuss Lily’s insecurities about her appearance, and she’s heard singing, “I wish I looked just like Cheryl Tweedy”, though she later claimed no one wanted to look like the Girls Aloud singer, adding: “They just think they do.”
Cheryl was asked about Lily’s comments during an interview with chef Gordon Ramsay on his show ‘The F Word’, and branded Lily a “chick with a d***”, prompting Lily to publish an open letter to Cheryl.
She wrote: “Cheryl, if you’re reading this, I may not be as pretty as you, but at least I write and sing my own songs without the aid of Auto-Tune.
“I must say, taking your clothes off, doing sexy dancing and marrying a rich footballer must be very gratifying, your mother must be so proud.”
However, Lily took steps to patch things up with Cheryl in 2014, admitting she regretted the feud.
She told Q magazine: “I wish that whole thing hadn’t happened. I like Cheryl.
“She’s good on ‘The X Factor’, she’s pretty and she’s got balls. I like women who do well.”
The pair later shocked fans when they seemed to bury the hatchet once and for all in 2015, cosying up for pictures together at the British Fashion Awards.