will.i.am is reportedly sick of "playing second fiddle" to his TV co-star Jessie J.

The pair appear as judges and mentors on the UK version of hit show The Voice alongside Sir Tom Jones and The Script's Danny O'Donoghue.

Tensions have been reported between the judges in the past, and now sources are saying that wil.i.am is becoming frustrated with Jessie's outspoken nature.

"Clearly each of them wants to be the 'lead judge' and get the most camera time, but the main issue seems to be between will and Jessie - he said he was fuming that she's 'trying to turn it into the Jessie J show,'" an insider told British magazine Closer.

"As an A-lister, he's not used to playing second fiddle! Will thinks Jessie sometimes ups the drama with 'fake' emotion, and he's warned her he may be willing to point this out on the live shows.

"It's caused a bit of tension."

Meanwhile, Jessie is said to be unimpressed with her co-star's comments.

"She's telling everyone he should stay away from her during filming and it's making the team nervous," says an insider.