Australia had been the winter favourite for the Classic but lost that position when Kingman reappeared with a brilliant performance in the Greenham Stakes at Newbury earlier this month.
The vibes coming out of Ballydoyle regarding the son of Galileo and Ouija Board, two of the best racehorses of modern times, have been strong for some time, and O'Brien is also likely to call on Dewhurst winner War Command, who had been a possible for the French equivalent a week later. Others for O'Brien are Giovanni Boldini and Oklahoma City after a total of 17 contenders stood their ground.
O'Brien said: "We are happy with both Australia and War Command and it looks like both will run on Saturday. We'll finalise things after they go through all their tests [tomorrow]. That's the way we're thinking at the moment."
O'Brien added that Tapestry and Bracelet were intended runners in the 1000 Guineas on Sunday.
The Greenham was just the third race of Kingman's life, and rider James Doyle felt everything went like clockwork in his trial. "I'm looking forward to it," he said. "I've not sat on him since the Greenham. Rab Havlin rides him in all his work and sits on him every day, there's no need for me to go there. I rode him at Sandown [Solario Stakes] and then went for a sit on him before the Greenham so I know him well enough now.
"He was very good at Newbury but his ability has never been in question, it was purely to get a run under his belt. It's all systems go."
Gosden has said since the Greenham that Kingman would not run on unsuitably quick ground but that now looks unlikely after clerk of the course Michael Prosser applied five millimetres of water to the track on Monday. There is also rain due on Thursday, which could be anything between four and six millimetres. The going is currently described as good to firm.
Richard Hannon is another with multiple chances, in what is his first season holding a licence since taking over from his father. The unbeaten Craven Stakes winner Toormore heads his team, supported by Night Of Thunder and Shifting Power.
Roger Varian's Racing Post Trophy hero Kingston Hill brings a solid profile to the table, while the William Haggas-trained Ertijaal, victorious on All-Weather Championships Finals Day at Lingfield on Good Friday, is another improver.
There is significant overseas interest, too, in Noozhoh Canarias, the first ever Spanish-trained contender.