The Dewhurst Stakes winner is one of 11 possibles trained by Aidan O'Brien, who has already taken the Rowley Mile Classic seven times.
Among other leading candidates from O'Brien's Ballydoyle yard are the unbeaten Phoenix Stakes victor Caravaggio and War Decree, winner of the Vintage Stakes at Glorious Goodwood.
The Criterium International and UAE 2000 Guineas winner Thunder Snow tops six from trainer Saeed bin Suroor, while Racing Post Trophy scorer Rivet is a strong entry from the William Haggas stable.
National Defense, easy winner of the Prix Jean-Luc Lagardere at Chantilly in October, is one of four French entries.
His trainer Criquette Head-Maarek plans to give the son of Invincible Spirit a prep run at Maisons-Laffitte next month.
"National Defense has done extremely well over the winter and worked on the grass for the first time this year on Tuesday," she said.
"The going was terribly soft but that didn't seem to be an issue for him and he went nicely. He looks really good at the moment - he has put on a lot of weight and has a shiny coat - but he does need some sun.
"I plan to run him in the Prix Djebel over the straight seven furlongs at Maisons-Laffitte on April 10, by which time I hope to have him at about 90 per cent, leaving a little to work on. After that we will decide between the Qipco 2000 Guineas and the Poule d'Essai des Poulains."
She added: "Because of sickness, last year was a disaster for a lot of trainers and my string was hit really hard, so National Defense made my season by winning a Group One. But he was affected (by the virus) earlier in the year, just like all the others.
"He is a galloper who does not like to be restrained, otherwise he won't breathe properly, though I would love to see him settle better in behind. I hope Pierre-Charles Boudot will be available to ride him as he knows him very well and has learned that he is not a horse that you can fight."
