The music producer missed his flight back to the UK.
Will.i.am has been accused of leaving his 'The Voice' acts in the lurch for a second time.
The 37-year-old music producer flew out to the United States on Monday and was due back for Thursday afternoon but missed his flight.
An insider told the Mirror: ''Will's acts think he's putting his own career first a lot of the time and it shows when Tom spends so much time with his.''
The source added: ''He can get away with it because his artists aren't performing this weekend, but they're still rehearsing. They feel like they can't depend on him.''
Will, who has been working on his new single, has admitted he does not voice coach his team, while Sir Tom trains with his five times a week.
He said: ''I've just got a different approach. My coaching is, 'Hey, let's talk'.''