By Georgina Littlejohn
Squaring up: Ryan Seacrest confronts Simon Cowell on last night's American Idol over remarks made about contestant Michael Lynche
The American Idol host took exception to Cowell's comments about male finalist Michael Lynche, whose performance was slammed as 'desperate' and 'corny'.
Typically earning a chorus of boos and hisses from the audience, Cowell, 50, just smiled smugly as Seacrest, 35, challenged him to elaborate on his remarks.
Cowell said: 'Do you want me to talk to you or to Michael?'
And while the other judges - Randy Jackson, Ellen DeGeneres and Kara DioGuardi - tried to laugh it off and carry on, Seacrest was not going to let it drop
Their bitchy banter has become as much a part of American Idol as the tears, tantrums and triumphs.
And while most of Simon Cowell and Ryan Seacrest's bickering is all done affectionately and very tongue in cheek, sometimes things can get rather heated.
Last night was no exception, as Seacrest squared up to judge Cowell in defence of male finalist Michael Lynche, as the final 12 contestants performed songs by the Rolling Stones.
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Calm down: Cowell tries to reason with Seacrest as judge Kara DioGuardi laughs the spat off
You win: Cowell backs away from an angry Seacrest
In front of a stunned and silent studio audience, Seacrest walked off stage and approached the judges, put his hands on the desk and leaned towards Cowell.
In hushed tones, he said to Cowell: 'I'm actually trying to help him out a little bit because I want him to stay in this competition. Are you all right with that?
'Try and give him some constructive criticism.'
Defensive: Contestant Michael Lynche stands by as Seacrest takes Cowell to task
Holding his hands up, Cowell backed his chair away from the desk - and an irate Seacrest - and told him: 'This is getting very uncomfortable. We can sort this out later in my trailer if that's what you want.'
It was then business as usual as the remaining eleven contestants stepped up to perform.
Cowell and Seacrest have always insisted that their bickering on the show is all just a bit of fun and they are great friends off-camera.
Some gossip columns in the US have even suggested that their spats are scripted as a ploy to spice up the show and draw in more viewers.
Bickering between the judges and the host hasn't done the X Factor rating any harm, especially the spats between Dermot O'Leary and judge Louis Walsh.
Not backing down: Seacrest waits for a reaction from Cowell
Two years ago they nearly came to blows after O'Learly indulged in a number of camp jibes towards Walsh, but was said to have apologised to the music producer after a ticking off from X Factor bosses.
And last November they engaged in a row on air after O'Leary dismissed his comments about Joe Elderry's performance of Circle of Life.
He said: 'Every now and then Louis needs to be put back in his box.'
Walsh said: 'You're not a judge Dermot, I'm a judge', to which O'Learly snapped back, 'I think the audience are the real judges."
Smug: Cowell just smiles at Seacrest as the audience look on in amusement