Image copyright PA Image caption Sir Tom Jones is returning to The Voice, joined by Jennifer Hudson, Gavin Rossdale and Will.i.am

Sir Tom Jones has said getting dropped from The Voice shows its contestants that even established stars have to cope with rejection.

Speaking at a press launch of the sixth series of the show, Sir Tom added he was pleased ratings went down when he was not featured as a coach.

"Whoever was responsible made a mistake," said the Welsh singer.

He was invited back after ITV bought the rights to broadcast The Voice, previously shown on BBC One.

'Their loss'

Sir Tom said it was not the BBC that was behind the decision to no longer have him on the show, but "the people on The Voice, whoever, the powers that be".

"I did a show on the BBC right after that - Children in Need, with Rob Brydon," he noted. "I wasn't really upset with the BBC. But whoever was responsible made a mistake."

Sir Tom spoke of the importance of artists believing in themselves because "you're bound to get knockbacks".

"There's a knockback right there, at my time of life - to prove to these young singers coming on the show that even I got a knockback, after all that time.

"Then you've got to think - it's their loss. I knew what the public felt because of the feedback I had.

He recalled a time he entered talent competitions himself, in south Wales - much to the amusement of his fellow coaches.

"I lost out to a ventriloquist once - and she was terrible," he mused. "I had to walk away from that."

Image copyright Getty Images Image caption Sir Tom said he was hoping to do live shows later this year

Will.i.am, the only coach to have featured on every series of the talent contest, said the lack of chart success for its previous winners has been "down to song choice".

The debut single by Kevin Simm, the former Liberty X singer who won the last series, peaked at 24 in the charts.

Black Eyed Peas rapper Will.i.am said the new prize of a record deal with Polydor would change things.

"It comes down to song choice. I think that's one of the reasons we've not seen a real star from the show. The songs they've been singing [have been] like… whatever."

And talking about the show going up against BBC singing competition Let It Shine, fronted by Gary Barlow, he said: "We have people coming up against us, thinking they can slide right around our time slot - so what.

"We're the headliners - watch The Voice, see the drama, see the amazingness, boom."

Barlow has since tweeted a response, saying: "Good luck to everyone on @thevoiceuk good honest competition makes us all better."

'Emotionally invested'

The Voice has a new twist that means the judges no longer speak to the contestants if none of them has chosen to turn their chair around - indicating they want them in their team.

New coach Gavin Rossdale, lead singer of Bush, said it was difficult seeing the disappointment on the faces of those who had been unsuccessful.

Image copyright PA Image caption Kevin Simm (far right) won the last series of The Voice

"I'm having so much fun - I wasn't expecting to have that much fun all the time," he explained. "The only thing that's been a bit hard is seeing some of the contestants that didn't make it, and we see their story - I could feel myself sinking lower and lower. I was feeling bad."

He said one of the reasons he wanted to be a coach was because of "how emotionally invested you get in the contestants".

"You can't help yourself. You're caught up in the dreams they've had for years."

Rossdale, the father of model and Strictly Come Dancing contestant Daisy Lowe, said: "We can help one person. We're just preparing them.

"We're real coaches - it's the FA Cup final, they go out there and play it, it's up to them. But it's good if they win!"

Image copyright Getty Images Image caption Jennifer Hudson said she feels "empowered" as a coach

Oscar-winning actress and singer Jennifer Hudson - a former contestant on singing contest American Idol, who came seventh on the show in 2004 - said of being a coach: "It's so good. I'm really enjoying this experience and working with these guys, and being on the other side.

"I can't believe I'm here because it's still so fresh in my mind, when I was a contestant and trying to get here. But I feel empowered because I feel like I can help them get there."

She said she was a "firm believer in taking the opportunity you're given" - adding that failing to win a show did not mean you could not be a success.

"No-one is going to live your dream for you - no one is going to chase your dream for you," said Hudson. "It's something everyone should keep in mind. You have to go out there.

"This is the type of thing you cannot do unless you're passionate about it. Other than that, you just go home."

The sixth series of The Voice starts on 7 January on ITV at 20:00 GMT.

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