O'Brien, who will also saddle Tumblebrutus, is seeking his third win in the 2,000 Guineas, which is sponsored this year by Ultimatebet.com. He previously won with King of Kings in 1998 and Rock Of Gibraltar in 2002.
Other leading contenders are Haafhd, the impressive winner of the Craven Stakes two weeks ago for Barry Hills, and undefeated Salford City, winner of the Greenham Stakes for David Elsworth. Haafhd starts from stall four and Salford City drew the sixth.
Godolphin, chasing its third 2,000 Guineas as well, also entered two horses -- Snow Ridge (stall 14) and Golden Sahara (stall 5).
Dermot Weld's Grey Swallow (3) and John Oxx's Azamour (11) complete the Irish hopes this year, while Whipper (8), trained by Robert Collet bids to be the first French-trained winner since Pennekamp nine years ago.
There has been light rain at Newmarket with more showers expected, although the course is in good shape.