Sarah Murdoch flaunts her wealth with a pair of $660 sunglasses as she cools down with Bill Gates at Australian Open in Melbourne

Sarah Murdoch flashed her expensive style on Friday as she attended Day 13 of the Australian Open at Rod Laver Arena in Melbourne.

Rubbing shoulders with Microsoft co-founder Bill Gates, the British model and wife of media mogul Lachlan Murdoch flaunted her wealth with designer accessories. 

Slipping into a simple black tank top, she paired the frock with some $660 sunglasses from French luxury fashion house Celine.

Sweeping her blonde tresses back from her face, Sarah, 53, was all smiles as she happily chatted with Bill, 70, while they watched the Men's Singles Semi-final match. 

Meanwhile, the US billionaire kept his face shaded with a navy blue cap as he and Sarah cooled down with small fans.

It is the second day in a row Bill has been spotted at the annual sporting event this year, as the tech mogul mixes in with Aussie A-listers in the premium seats.

Also in attendance on Thursday was former AFL star-turned-TV personality Sam Newman, who appeared deep in concentration while watching the on-court drama.

Australian comedian Andy Lee was also spotted soaking up the action alongside his partner Rebecca Harding.

Veteran journalist Liz Hayes was another familiar face in the stands, cutting a stylish figure in a chic cream blazer as she followed the match with interest from courtside.

Basketball legend Andrew Gaze was also spotted in the crowd, with the former Boomers captain looking every bit the sports fan as he watched the action unfold.

It follows reports that Bec Judd had recently cemented herself as the queen of the WAGs with her glamorous appearances at the Australian Open over the past week.

And the wife of AFL star Chris Judd may be shelling out a pretty penny for her prime position courtside at the tennis tournament in Melbourne.

The 43-year-old was spotted sitting in on-court seats at matches this week - and the true cost of that privilege has been revealed.

On-court seating at Rod Laver Arena can run as high as $20,000, with the popular spots already sold out.

Bec was in A-list company, with other celebrities in her section including Scottish actor Gerard Butler and Jaggad co-founder Michele Greene.

The ticket price doesn't just include an unrestricted view of the tennis court.

Also offered up is a meal made by top chef Shimpei Raikuni from Brisbane's Sushi Room, which is served in a private dining space.

Additionally, Piper Heidsieck champagne is served, and a chauffeur is on hand to take guests to and from the venue.