John Reid will partner Fantastic Light in Saturday's King George VI and Queen Elizabeth Diamond Stakes after the surprise withdrawal of his intended partner Kayf Tara.
Reid learned of the switch this morning when Godolphin decided to withdraw the Gold Cup winner from the #750,000 Ascot showpiece.
It means that Richard Hills, originally pencilled in for Fantastic Light, misses out in the big race.
Reid's agent Peter Shoemark said: 'The news was a surprise to us.
'As far as we were aware Kayf Tara was going to run until the secretary from Godolphin telephoned to tell us the morning that the horse had been taken out. They didn't give a reason.
'But of course Fantastic Light is jointly owned by Maktoum Al Maktoum and Godolphin and John does have a retainer with Sheikh Maktoum.
'John has ridden Fantastic Light several times including last time out in the Eclipse. He's a decent horse though Montjeu is going to be extremely tough to beat.'
Reid is gradually climbing the jockeys' table after a slow start to the season.
'John had been a little quiet due mainly to his yards, especially Ed Dunlop's, being quiet. But Ed is firing now and things are getting much better for John,' said Shoemark.
