World No. 1 Rory McIlroy along with girlfriend, Caroline Wozniacki climbed to the highest building in the Southern Hemisphere – the Sydney Tower.

The duo donned special suits to undertake a sky walk around the 309 metre or 1,014 feet high structure located right in the heart of the Sydney CBD.

Wozniacki tweeted:  “Really proud of myself, on top of the world in  Sydney with @McIlroyRory! #afraidofhights”.

Wozniacki is in the 2000 Olympic Games host city to compete in the Apia Sydney Tennis International and desperate to find form ahead of the up-coming Australian Open and the first Grand Slam event of 2013 after crashing out in the first round of last week’s Brisbane International.

The couple did the full Sydney tourist trek taking in Sydney Harbour icons as the Sydney Opera House and Sydney Harbour Bridge, and while McIlroy and the Danish tennis ace undertook the Sydney Tower walk they seemingly passed up on the Harbour Bridge Climb.

It is McIlroy’s first visit to Australia’s largest city and comes just weeks after the controversy surrounding attempts made by Golf Australia for the double Major winner to contest the Emirates Australian Open.

There was claims in local Australian newspapers McIlroy was all set to contest the prestigous event but that his appearance fee doubled to $2m after he captured the PGA Championship at Kiawah Island.

McIlroy will remain in Sydney with Wozniacki ahead of flying out for Dubai where he begins pre-season testing with his new Nike clubs on Monday January 7th at the Els Club.

And a week later in Abu Dhabi, McIlroy will be officially introduced to the sports world as a Nike staff player.

Arrangements are in place for the official Nike annoucement to made in the UAE capital early in the evening of Monday January 14th.

Rory McIlroy and Caroline Wozniacki on top of the 309 metre Sydney Tower, the highest building in the Southern Hemisphere.

Rory McIlroy and Caroline Wozniacki at Circular Quay in Sydney with the famed Sydney Opera House in the background.