The former 4 Non Blondes star took to social media on Monday (18Jan16) to attack Gaga's Academy Awards mention for her Diane Warren collaboration Til It Happens to You.
Perry claimed she had it on good authority that the Poker Face singer was simply the performer of the song, and didn't deserve a writing credit.
She tweeted, "I have Diane's original demo with her singing. The only line that has been changed (is) 'Till you're at the end, the end of your rope' originally was 'Til you got a hole ripped in your soul'. So I guess technically one line was changed so sure Gaga possibly 'rewrote' a line. But chances are Diane still took part in rewriting that line which means Gaga contributed a few words. Is that writing. Not in my book."
Perry, who insists she "loves" the finished product, went on to suggest Gaga was only given a co-writing credit to boost the exposure of the track.
However, Warren has since responded to the claims on her own Twitter page, insisting Gaga's input helped make the single Oscar-worthy: "The song is the result of a special collaboration between myself and Lady GaGa," Warren wrote.
"When I called her and played her the song, it was more of a sombre ballad, but she really made it epic," she told Billboard.com. "She made it hers and took it to another level by arranging the s**t out of it and singing the s**t out of it."
Perry appears to have checked her facts, as hours later she posted an apology to Gaga, which read: "My sincere apologies. I made a mistake to comment. I wasn't in the room when the #TIHTY was being written. More importantly, I wish the focus to remain on the great importance of the song and the message of the film."
Gaga and Warren's song was written as the theme for 2015 campus rape documentary The Hunting Ground. It will compete with Earned It from Fifty Shades of Grey, Manta Ray from Racing Extinction, Youth's Simple Song #3 and Sam Smith's epic Spectre tune Writing's On The Wall when the Best Original Song Oscar is handed out at the 2016 Academy Awards next month (Feb16).
Perry missed out on a nod in the Best Song category at this year's Oscars for her tune Hands of Love, a song written for movie Freeheld's soundtrack that was performed by Miley Cyrus.