Jessie J has been accused of snubbing BBC One's controller after he tried to congratulate her on The Voice UK's success.
The 'Price Tag' singer refused to speak to Danny Cohen and left him standing outside her dressing room, The Mirror reports.
She is consequently facing being axed from The Voice UK after staff branded her a "diva" who has become "impossible" to work with, it is alleged.
"Jessie is getting far too big for her boots. Nobody can believe what an impossible diva she has become. It was extraordinary, Danny is the most senior man at BBC One and The Voice is his baby," a source said.
"He was the man who gave Jessie J a job and turned her into a household name, so nobody could believe it when she left him standing outside in the corridor like a lemon. It was made clear that she was too busy to see him.
"It's not a smart move to do that to the man who makes the big decisions. Everybody else at the studio was bending over backwards to be nice to Danny, but Jessie didn't seem to care who he was."
Jessie J previously angered producers after describing elements of the show as "lame" and admitting that she didn't watch the series after it was recorded.
Sources also criticised the coach, who is said to earn a six-figure sum for her role on The Voice UK, for being unapproachable and arriving late to the studio with a huge entourage.
She also told Closer magazine that she would never audition for the show, saying: "I wouldn't enter myself. I feel like I've worked hard enough to stay here, even if I end up behind closed doors doing make-up. I'll always be around."
The BBC last night insisted that Cohen has a good relationship with all of the show's stars.
