Paramore's Hayley Williams says that One Direction "ripped off" part of their new single Steal My Girl from a New Found Glory song.
The singer is dating NFG guitarist Chad Gilbert and says the intro was taken from one of their tracks.
In a series of tweets, she claimed the 1D song "couldn't sound any more like" the beginning of It's Not Your Fault.
She stopped short of blaming the band, instead saying it was "more to do with whoever pitched or co-wrote the song".
Her comments come after Gilbert posted similar accusations earlier this week and faced a backlash from 1D fans.
He tweeted: "Props to the One Direction 'Steal My Girl' single for reworking the 'It's Not Your Fault' piano part into a Top 40 single. Let me get a cut."
Despite later dismissing his remarks as "a joke", some Directioners took offence and sent abusive tweets to Jones.
After calling them "nuts fans", he tweeted directly to One Direction asking them to speak to their fans about their abuse.
"Your fans spew the most racist/homophobic/sexist hate I have ever seen on the Internet... You have a platform to change that," he wrote.
Minutes after her initial tweet, Williams also said she expected to receive "hate" from 1D's "very large fanbase".
Julian Bunetta co-wrote Steal My Girl with John Ryan, Ed Drewett and Wayne Hector as well as Louis Tomlinson and Liam Payne.
Other critics say the song sounds similar to Journey's Faithfully.
Speaking to MTV, Bunetta said he didn't have that track in his head when they wrote Steal My Girl.
"When we sat down and played the piano lick, nobody had any references in their head about what they wanted to write or anything and then I saw all the things about that [Journey song]," he said.
"At the end of the day, the lyric and the melody have nothing to do with any other song that I have ever heard.
"Sometimes there's only so many things you can do with a piano at that tempo.
"There is an age-old saying that great minds think alike so, naturally, sometimes people are going to write on the same inspirational wave lengths and come up with things that are similar and it wasn't anyone's intention to do that at all."
There's been no response from One Direction about either accusation as yet.