American Idol may be over forever , but the decade-long tension between original Idol Kelly Clarkson and highest-earning Idol Carrie Underwood seems like it will never end! RadarOnline.com has exclusively learned that – at last night's finale taping – the 33-year-old blonde country superstar "threw a fit" over Clarkson's performance backstage! Click through seven epic behind the scenes photos inside the last Idol cat fight ever!
Season four Idol winner Underwood – who is the highest earning Idol of all time with a net worth of $75 million – belted out a duet last night with longtime Idol judge and friend, Keith Urban, 48.
But according to a production source on the hit show – which ended its 15-year-run on Fox this season – "a duet was not what Carrie wanted!"
"Carrie caused serious drama with the final production of the show because she flipped out that she was stuck doing a duet when she has a tour and so many things to promote right now," the insider claimed.
- 'No Wiggle Room': Katy Perry Quit 'American Idol' After ABC Bosses Refused to Raise Eight-Figure Salary: Report
- Katy Perry 'Distances' Herself From Ryan Seacrest on Set After Announcing 'American Idol' Exit
- Katy Perry Quits 'American Idol' After 7 Seasons, Walks Away From $25M Salary to 'Feel That Pulse of My Own Beat'
"Carrie wanted to perform on her own, and the producers knew that," said source.
Underwood's eight-year grudge against Clarkson, 33 – who was the first to win the singing competition show in 2002, yet has a net worth of $24 million less than Underwood – took a nasty turn last night when Clarkson was given an entire segment of the show to do a medley of her greatest hits!
"Carrie said she just felt like she should have gotten the same type of treatment that Kelly did since she is the big money-maker from the show," the source told Radar. Underwood's rep did not immediately respond to Radar's request for comment.
Do you think that Carrie Underwood had the right to be upset over Kelly Clarkson getting an entire segment? Tell us your thoughts below.