Brittain said: "The extra furlong will be no problem to her. She will be fit enough to do herself justice and she should be able to find a couple of lengths' improvement. We're looking forward to taking on Special Duty again in the Guineas.
"The form can turn upside down from two to three but Misheer has learned to relax in her work. She quickens up and she is a very similar filly to Seyyedati."
Misheer, who renews a rivalry with the Brian Meehan-trained Lady Of The Desert, a head behind her in the Cheveley Park, is 25-1 with Victor Chandler but 16-1 with Ladbrokes for the Guineas.
Music Show is 7-1 joint second-favourite for the Classic following her victory in the Nell Gwyn Stakes at Newmarket yesterday.