Camelot also won the 2000 Guineas in a stellar three-year-old campaign and was just denied the Triple Crown by Encke in the St Leger, before being unplaced in the Arc.
Shortly after his trip to France he developed colic but has made a full recovery and was seen moving well in a public gallop at the Curragh recently.
“I’ve been delighted with him since he came back, he’s shown all the speed and the class that he always had,” O’Brien told At The Races.
“I’m really looking forward to him.
“I think he’ll come back to the Curragh for the Mooresbridge (May 6), if everything then goes well hopefully he’ll go to the Tattersalls (Gold Cup) and then he might go to the Prince of Wales’s.”
O’Brien also had news of his two Dubai winners, St Nicholas Abbey and Lines Of Battle.
“Races like the Coronation Cup and the King George are likely for St Nick, we experimented a bit last year with different ways of riding him and different trips but Joseph and Derrick (Smith) were adamant he wants to be ridden handy this year and that’s what they did,” said O’Brien.
“The plan for Lines Of Battle is the Kentucky Derby, he seems to have come out of the race well, travelled well and in an ideal world he would have preferred a better lead but that was the way the race worked out.”
Breeders’ Cup Juvenile Turf winner George Vancouver is the star name among the 18 entries for the 2,000 Guineas Trial at Leopardstown on Sunday.
O’Brien’s Henrythenavigator colt – mentioned favourably by the trainer after galloping at the Curragh last month – was third to Dawn Approach in the Dewhurst before travelling to America, where he ran out a decisive winner.
O’Brien has also entered Festive Cheer, Flying The Flag, Francis Of Assisi, Magician and the once-raced The United States.
Jim Bolger has started the season in red-hot fashion and has Trading Leather, Dewhurst runner-up Leitir Mor, Move To Strike and Alpinist to choose from.
Mick Halford’s Dibayani, Tommy Carmody’s Fort Knox, High Octane from John Murphy’s yard and David Wachman’s Fighter Squadron are other interesting contenders.
Richard Hannon’s Moyglare winner Sky Lantern is one of 14 possibles for the 1,000 Guineas Trial.
O’Brien is again strongly represented, with Snow Queen, Magical Dream and Greek Goddess all entered.
Bolger’s Bunairgead, John Oxx’s What Style and Wachman’s Hint Of A Tint all look promising types.
Battle Of Marengo is the star name among six O’Brien-trained entries for the PW McGrath Memorial Ballysax Stakes at Leopardstown on Sunday.
The first recognised Derby trial of the Irish Flat season, the Ballysax Stakes has been a breeding ground of future Ballydoyle champions down the years, with O’Brien saddling six previous winners, including Galileo, High Chaparral, Yeats and Fame And Glory.
Battle Of Marengo won three of his four starts as a juvenile, and signed off with an impressive display in the Beresford Stakes at the Curragh.
O’Brien also has Eye Of The Storm, Foundry, Magician, Nevis and The United States engaged in the Group Three contest.
Another trainer with an outstanding record in the Ballysax is Jim Bolger, who has saddled seven previous winners of the race, including in the last three renewals.
The pick of three entries this year could be Trading Leather, who won twice from four two-year-old appearances and was a fair fifth in the Racing Post Trophy at Doncaster. Bolger has also entered Alpinist, a winner on the opening day of the new season at the Curragh, and Beyond Thankful.
Fourteen horses have been entered in the 10-furlong event, with Dibayani, High Octane, Imperial Concorde, Little White Cloud and Sugar Boy completing the field.