Trainer Mark Johnston has revealed top filly Attraction will miss the Queen Anne Stakes at the Royal York meeting.
The horse is recovering from a minor leg sprain, sustained when racing in Hong Kong, which is taking longer to heal than anticipated.
Johnston hopes Attraction will return in Newmarket's Falmouth Stakes in July, where her unbeaten run ended in 2004.
Attraction won last year's English and Irish 1,000 Guineas before claiming the Coronation Stakes at Royal Ascot.
Johnston told his own website: "She is sound and continuing in ridden exercise. It has been decided that she should have more time."
The 2005 Royal meeting, which takes place from 14-18 June, is being held at York while Ascot racecourse is redeveloped.