Luke Bryan is to judge 'American Idol'.

The 41-year-old country singer has reportedly signed up to sit alongside Katy Perry on the panel of ABC's rebooted version of the popular talent show, just a week before auditions are due to begin.

According to TMZ, Luke hasn't yet signed a contract but is expected to do so in the coming days.

Sources told Variety the show plans to have a panel of three judges, rather than four.

And while Lionel Richie was said to have been in advanced talks to join the programme, he is no longer in the running, while other artists who are in consideration include Charlie Puth and Keith Urban.

However, Keith recently ruled himself out, insisting no one who had been on the judging panel when the show broadcast on Fox would be joining host Ryan Seacrest in making a comeback.

He said: ''I think it's going to be all new people except for Ryan.''

ABC declined to comment on Luke's signing.

Meanwhile, 'Bon Appetit' hitmaker Katy - who has landed a reported $25 million contract for the show - said she was ''honoured and thrilled'' to be involved with the programme when her signing was unveiled in May.

She said: ''I am honoured and thrilled to be the first judge bringing back the 'American Idol' tradition of making dreams come true for incredible talents with authentic personalities and real stories. I'm always listening to new music, and love discovering diamonds in the rough - from mentoring young artists on my label, or highlighting new artists on my tours, I want to bring it back to the music.''

And network chiefs were delighted to get Ryan back on board as host.

In a statement, ABC Entertainment president Channing Dungey said: ''So much of 'American Idol's overwhelming success can be attributed to Ryan, whose larger-than-life personality and laudable dedication to creating quality entertainment has made him a true master of his craft. His talent is limitless, and I can't think of a more appropriate person to honour the Idol legacy as it takes on new life than the man who has been there through it all.''