article: Rory McIlroy was joined by Niall Horan at the Masters on Wednesday and the World's best golfer is set to return the favour by singing on stage with the One Direction star at the end of the summer. Horan fell while caddying for the Northern Irish golfer in the traditional Par-3 Contest at Augusta while he also hit a ball into the water on the ninth tee, but the Irish singer will get some payback in September. McIlroy is set to compete at the Deutsche Bank Championship which occurs a few days after One Direction play Gillette Stadium in Massachusetts on September 12 - and Horan revealed that the pair will reunite on stage in Boston. One Direction singer Niall Horan caddied for Rory McIlroy in the traditional Par-3 Contest at Augusta National . Horan had a embarrassing moment when he slipped over while carrying McIlroy's clubs on the  course . Sky Sports' cameras captured the moment when Horan suffered a slip while caddying for McIlroy . McIlroy steps aside to let the One Direction singer Horan tee off on the ninth hole at Augusta National . The Masters official Twitter account shared an image of Rory McIlroy and Tiger Woods with Niall Horan . 'That was part of the deal,' Horan told the Golf Channel. 'If I went on the bag with him, he would come on stage and sing with us. 'He's playing in the Deutche in Boston at the end of the summer and we're playing in the Gillette Stadium in Foxboro in the same week, so we going to get him up. 'He said if he's allowed pick the song then he's going to do it.' Asked whether he has ever heard McIlroy in full voice, Horan replied: 'No, but apparently, he's terrible.' Augusta National's par-3 course traditionally hosts the Par-3 Contest the day before the first major of the year .
highlights: Rory McIlory was joined on the course by Niall Horan for Par-3 Contest .
  The One Direction star suffered an embarrassing slip while carrying McIlroy's clubs during the round on Wednesday .
  McIlroy shot a one-under-par round to finish in a tie for 16th .
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   One Direction singer Niall Horan caddied for Rory McIlroy in the traditional Par - 3 Contest at Augusta National . Horan 
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