Image copyright Getty Images Image caption Coldplay performed at the American Music Awards last month

Coldplay are to headline the half-time show at Super Bowl 50 - with Chris Martin describing it as the "greatest moment" in the band's career.

The frontman said the band was "excited and honoured and thrilled" to take part in next February's event.

They revealed the news on Twitter, saying the show would reflect the past, present and the next 50 years ahead.

A record 118.5 million viewers in the US watched Katy Perry perform in this year's half-time show.

The National Football League (NFL) promised "fun, celebration and surprises" for the event at Levi's Stadium in Santa Clara, California.

Recent half-time headliners have also included Beyonce, Bruno Mars and Madonna, with Bruce Springsteen and The Who also playing in past years.

'Special guest'

In a promotional video, Martin said: "We are so excited and honoured and thrilled to be playing the half-time show.

"It's going to be wonderful and I hope we see you there."

The band's artistic director, Phil Harvey, said there would be a "special guest" - but did not reveal their identity.

Admitting he was full of nerves over the event, he said: "Today, it's about how do we stage our special guest. Yesterday, what I was nervous about was all about the set list."

Martin said he was also "really, really nervous".

"This is the greatest moment in our band's life," he said. "We are going to give it everything we have."

Image copyright PA Image caption The band played at a church in Hackney for the Annie Mac show on Thursday night

The video showed Coldplay discussing plans for the extravaganza, with talk of an LED floor - and Martin joking "are those our outfits?" when elaborate feathered costumes were seen in the clip.

It comes as the band released their seventh album, A Head Full of Dreams, on Friday. All of their previous albums have reached number one in the UK.

Coldplay played a gig at St John at Hackney Church in east London on Thursday, broadcast live on Annie Mac's BBC Radio 1 show, ahead of the album launch.

Free show in Paris

The band are planning to tour "early next year", after only playing a handful of low-key shows to promote their last album, Ghost Stories.

It was also announced on the band's website that they were to play a free show in Paris for their French fans on 9 December, weeks after the attacks in the city that left 130 dead, including many at the Bataclan theatre where the Eagles of Death Metal were performing.

Martin said: "Paris is a very special city for our band. It's a place of unequalled grace, spirit and beauty and we can't wait to play this show."