He may have just signed for Harlequins, but Australian lock James Horwill has far more weighty matters on his mind right now.

The 29-year-old is set to play a key role in the Wallabies 2015 Rugby World Cup campaign, and his three-year deal at the Stoop starts at the conclusion of international hostilities.

Australia kick-off their World Cup against Fiji on September 23, and should it be a successful campaign, the final at Twickenham is on October 31.

Only then will Horwill turn his attention to a new stage in his career on the English domestic scene.

The CV of the former Aussie skipper includes leading the side to Tri-Nations glory in 2011 and to third at the World Cup of the same year.

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As captain of Queensland Reds, Horwill won the Super Rugby title in 2011 and made more than 100 appearances for the Brisbane-based side.

He said: “As hard as it will be to leave Ballymore [spiritual home of the Queensland Reds], my team-mates, the staff and all my fans and friends in Queensland, I’ve been offered a fantastic opportunity with Harlequins to experience rugby in another part of the world.

“This is right for me at this stage of my rugby career.”

He added: “I’m completely committed to helping the Reds and Australia achieve success in this World Cup year and then I’ll turn my attention to the next chapter of my life in rugby with Harlequins.”

Quins director of rugby Conor O’Shea said: “I’m delighted that we’ve attracted someone of James’ standing to play for us.

“James is known around the world not only for his uncompromising style of play, but also for his strength of character.

“He will be an asset for us on the field and within the changing room.”