The Voice judge has come under fire by the BBC for plugging his smartphone watch live on air.

The Black Eyed Peas frontman could be in line for a slap on the wrist from The Voice producers after he used the accessory during the show’s final on Saturday night.

The musician used the gadget to take a phone call from his pal Cheryl Cole, despite the channel’s strict advertising and product placement ban.

Cheryl had called him to praise his winning act Jermain Jackman for his rendition of Miley Cyrus hit Wrecking Ball.

This isn’t the first time the star has landed himself in hot water as he was previously banned from wearing a jacket embroidered with the words Go Hard Or Go Home, after he was accused of using the slogan to plug his 2011 single T.H.E. (The Hardest Ever). spoke of his latest gadget when wearing his smartphone watch during a recent appearance on Alan Carr: Chatty Man.

He said, “It takes my heartbeat, my calorie burn, you can make purchases from it. I started the company and funded it and used my own money to develop it.”