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Chris Martin was a busy man at a festival in the U.K. this weekend. 

First he and his Coldplay bandmates headlined BBC Radio 1's Big Weekend event Saturday night in Glasgow, Scotland.  And then the frontman stuck around for Day Two to make a guest appearance during the Kings of Leon set. 

Martin added some acoustic guitar to the Kings' live favorite "Fans," but he didn't do much singing.  Still, Kings of Leon frontman Caleb Followill joked as Chris walked off the stage that it was nice to "finally have someone famous in [the] band." 

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