Coldplay's song Viva La Vida is on the Grammys shortlist
Grammy nominees Coldplay have denied claims by rock guitarist Joe Satriani that they plagiarised one of his riffs on their song Viva La Vida.
In a statement on their website they said Mr Satriani "did not write or have any influence on the song".
Mr Satriani claims the track uses "substantial original portions" of his 2004 instrumental If I Could Fly.
The 52-year-old musician has filed court papers in Los Angeles and is seeking damages.
Coldplay are shortlisted for seven awards at February's Grammys, including song of the year for Viva La Vida.
"With the greatest possible respect to Joe Satriani, we have now unfortunately found it necessary to respond publicly to his allegations," the band said.
"If there are any similarities between our two pieces of music, they are entirely coincidental and just as surprising to us as to him.
"Joe Satriani is a great musician but he did not write or have any influence on the song Viva La Vida."
The group have asked him to "accept our assurances" over the song.
Viva La Vida is credited to the band's four members - singer Chris Martin, bass player Guy Berryman, guitarist Johnny Buckland and drummer Will Champion.
The song's title was inspired by Mexican artist Frida Kahlo.
It appeared on the album Viva La Vida or Death and All His Friends - which was released in June and went to number one in 36 countries - and was also one of their hit singles.
Satriani's track appears on his album Is There Love in Space?
'Bit of variety'
Meanwhile, Coldplay have announced a concert in Ireland, which will take place at Dublin's Phoenix Park on 14 September as part of next year's stadium tour.
Tickets for the performance will go on sale on Monday.
The band, who are going to be supported by Girls Aloud at their Wembley Stadium gigs, told BBC 6 Music why they chose the group.
"We wanted there to be a bit of variety and something that people might not expect from a Coldplay show," said drummer Will Champion.
Hip-hop star Jay-Z is due to support the band on some of their other dates.
Champion added: "Aren't they great? Jay-Z's the best within his field and Girls Aloud are the best in their field, no doubt. What more could you ask for?"