Coldplay dedicate song to singer they don't know

Coldplay's Chris Martin dedicated a song to a singer he doesn't know during the band's Sydney show. Photo/AP

Coldplay dedicated a song to Australian singer Angus Stone during their second show at Sydney's Allianz Stadium - even though the band have no idea who he is.

Singer Chris Martin said the idea came from a fan who levelled his ego after Coldplay's run of stadium dates made him feel like "the best thing since sliced bread."

"This kid came up to me and said 'you guys are good but not as good as Angus Stone'," Martin told Sunday's sell-out crowd.

"I said I don't know who that is and now I have to check it out but I'd like to dedicate this song to Angus Stone who brought me back down to earth today."

Martin should have no problem accessing the ARIA-winning singer's back catalogue considering Coldplay and Stone share the same label, EMI.

"Everyone I spoke to said he's great and so I send him my love and respect and thank you to that kid for making me feel from a billion dollars right back down to about two dollars," Martin said before launching into the song Warning Sign.

Coldplay's Mylo Xyloto tour wraps up in Brisbane on Wednesday.

The band recently played a sold out show at Mt Smart Stadium in Auckland.

- AAP