Liam Payne has admitted he "absolutely hated" Louis Tomlinson when One Direction first formed.
Both have put their differences aside now, but back when they first met during 2010's The X Factor, the two eldest members found themselves at loggerheads, according to The Sun.
Former bandmates Liam, 26, and Louis, 27, clashed over who they thought should be the leader of One Direction, which they formed with Harry Styles, 25, Niall Horan, 25, and Zayn Malik, 26.
Speaking on Hits Radio today Liam said: "When we were in the band it kind of felt like, because he was the oldest and because I'd been singing for quite a bit of time we both got put in a weird position.
"He was wanting to be the leader and I was doing my thing and wanted to.
"So at first we didn't get on at all. We absolutely hated each other, it was so funny. Really bad. We hid it well."
The pair are good friends now and recently met up for a mini reunion in Madrid last week.
Liam posted a snap to Instagram ahead of his gig: "Thanks for having me Madrid! Had a lot of fun last night. Good luck to @louist91 tonight for his first solo headline gig."
However, not all former bandmates are in a hurry to get into contact again, as Liam admitted he hasn't "seen or heard" from Harry Styles in a long time.
One pair of Directioners who may never bury the hatchet are Zayn and Louis.
The Kill My Mind singer said that when Zayn failed to show up for him after his mum passed away things never really recovered.
He exclusively told The Sun: "Truthfully it never really got better.
"I had a couple of calls with him after I lost my mum and all the boys had agreed to come to that performance and he didn't show so that really bugged me.
He added: "I've got goosebumps now. It was just seeing everyone there - Harry, Niall and Liam - that was what I needed that night, that support.
"So on the other end of the spectrum it kind of really showed. So, eh, I hope he's all right, but..."
He then gave the microphone a one-fingered salute.