Luxembourg will look to add yet another Group 1 to his illustrious CV in the LONGINES Hong Kong Vase before heading to stand as one of Coolmore’s National Hunt sires.

With top-level successes in the Futurity Stakes, the Irish Champion Stakes, the Tattersalls Gold Cup and the Coronation Cup, it's always tough to ignore the high-class five-year-old when it comes to Group 1 international contests.

The son of Camelot, who was last seen in the winners' enclosure at Epsom in May, was agonisingly denied a short-head by local hero Romantic Warrior in the G1 LONGINES Hong Kong Cup last year.

However, after posting a highly creditable fifth-place finish in the Breeders' Cup Turf over a mile and a half at Del Mar last month, the Ballydoyle team have opted to remain over twelve furlongs, where he'll meet the likes of former Melbourne Cup winner Without A Fight, Marco Botti's talented stayer Giavellotto and the William Haggas-trained Dubai Honour in the LONGINES Hong Kong Vase on Sunday.

O'Brien, who is seeking a fourth success in the race, said: "We thought he ran a great race last year.

"Last year he was coming home very well, and he was just beaten on the line, it looked as if we'd had run him over a mile and a half it would have suited him.

"He's been a great horse, big strong and consistent."

Luxembourg will be joined by fellow talented stablemate Continuous, who landed the St Leger Stakes at Doncaster last season.

The son of Heart's Cry started off this season with a win in the G3 Royal Whip Stakes, before placing in the G2 Prix Foy.

Despite underwhelming in his last two starts, O'Brien is keen not to dismiss his chances.

He said: "Continuous is probably more forward than he's been all year. Things haven't really worked for him yet this year, but he is in good form. A mile and a half and nice ground should be fine for him."

The Irish handler is also poised to launch a two-pronged attack in the G1 LONGINES Hong Kong Cup, with both Content and Wingspan ready to take their chance.

G1 Yorkshire Oaks winner Content leads the line, but has disappointed subsequently with below-par runs at Longchamp, Ascot and Del Mar, while her stablemate Wingspan will be hoping to go one better than when bumping into the exciting Kalpana in the G1 British Champions Fillies & Mares Stakes.

On both his fillies' chances, O'Brien said: "Content can be keen and we think the pace of the race will suit her. She ran in America last time and the pace wasn't really fast enough for her. We thought going back will suit and get her relaxed.

"We had the choice of the races for Wingspan, and we think the mile and a quarter will be fine for her."

Reflecting on returning to Sha Tin, and Hong Kong, for the International meeting O'Brien was positive about what makes him come back: "The supporters, fans, it's incredible really, and very exciting for racing all over the world. We can bring them together, we can get a rating on them and a handle on where the best horses are, and who is the best.

"This is a very special meeting."