Global co-workspace provider WeWork will become a key anchor tenant at 333 George Street, Sydney, which is owned by the Charter Hall Group's Prime Office Fund.
The lease takes the building's committed space to 100 per cent after practical completion in December.
It comes as the Sydney office leasing market is busy with the highest net effective rental growth of 5 per cent in the closing months of last year and expectations of improvements this year.
The latest office data is to be released on Thursday by the Property Council of Australia, in its biannual national office market reports.
Media giant Foxtel is one group in the market for 11,000-13,000 square metres when its lease expires at the AMP Capital's Thomas Holt Drive. The group has engaged Colliers International and is looking at the Sydney city fringe and lower north shore. One option is to join the rest of the business at the Lindsay Bennelong site at Artarmon.
The lease term is 10 years plus two five-year options with "generous car parking ratios required".
Another suggested move is by Accenture, whose lease at the GPT-owned Worplace6 property at Pyrmont, expires in 2020. The group could be the anchor tenant for Lendlease's timber building at Barangaroo, known as International House Sydney.
That building offers 6850 sq m across six storeys and was previously said to be the new home of WeWork, which has now taken the 333 George Street lease.
Should Accenture move, it is assumed the other tenant, Google, could take the space, which is about 7000 sq m. Google last year extended its lease at the Pyrmont site to 2021 as it awaits the redevelopment of the Bays Precinct at White Bay.
CBRE associate research director Felice Spark said the results came as the Australian office cycle reached the bottom, with national office vacancy peaking at 10.9 per cent at the end of last year.
"Sydney and Melbourne continued to see net effective rental growth during the fourth quarter of 2016 at 5 per cent and 2 per cent respectively," Ms Spark said.
"This rapid growth has broadly made up for the effective rental declines recorded between 2013 and 2015, with further increases forecast this year."
The 4300 sq m WeWork lease is across five floors comprising the outdoor terraces and extends the group's footprint in Sydney's Martin Place precinct as the construction of the light rail along George Street, the planned Sydney Metro line and upgrades to Martin Place make it the commercial heart of Sydney's CBD.
CPOF fund manager Craig Newman said the fund was "pleased to welcome WeWork to 333 George and we are excited about the community dynamic that their co-working environment will deliver for our other new tenant customers and anyone seeking work space in Sydney's CBD".
WeWork's head of real estate, Asia-Pacific, Evan Kleinberg said: "WeWork 333 George Street will add to our vibrant and growing community in Sydney and more specifically Martin Place. WeWork members will benefit from this location's central locale, ease of access, and strong amenities."
Along with WeWork, tenant customers that will call 333 George home include NAB, HSBC, Woolworths, Clyde & Co, AXF Group, Lockton Australia, AIMIA and Grimshaw Architects, the designers of 333 George.
CBRE's head of office leasing for Pacific, Andrew Tracey, said this was the first time in 20 years that such a small level of annual net supply had been added to Australia's office markets.