Louis Walsh has questioned Olly Murs' credentials as a singer.

Olly Murs

Olly Murs

The 'X Factor' judge has taken a swipe at Olly - who starred on the ITV series in 2009 - after he was recently announced as a coach on 'The Voice UK', saying his appointment is further proof that the singer is a "great hustler".

In response to the news, Louis said: "It's a job, it's a gig. Good for him. He's a great hustler. He's done very well for himself."

Olly also co-hosted 'The X Factor' for one series alongside his good friend Caroline Flack in 2015.

However, his presenting skills were called into question during his time on the talent show, and Louis has insisted Olly's appointment on 'The Voice' won't impact the popularity of 'The X Factor'.

Speaking to the Daily Mirror newspaper, Louis said: "It won't be as good as 'The X Factor' and it never will be. They've never had a hit."

Of Olly, he also asked: "Has he got a voice?"

Despite this, Olly recently insisted he's delighted to have become a judge on the show and is already looking forward to competing against the likes of Sir Tom Jones, Jennifer Hudson and will.i.am on the programme.

The British star - who has sold more than 17 million records around the world - shared: "I'm absolutely buzzing about being a coach on 'The Voice UK' and can't wait to sit alongside Will, Jennifer and Tom. I'm excited to mentor new artists and I'm in it to win."