3,500 News Corp employees will move to The Place in London Bridge Street starting this summer.
Following last summer's announcement that the UK arms of Rupert Murdoch's media empire will relocate to The Place – a newly-built office block next to the Shard – News Corp has now signed a 30-year lease for the building.
News UK – owner of The Times, The Sunday Times and The Sun newspapers – will move to the so-called 'Baby Shard' along with staff from Dow Jones and HarperCollins.
"There can be no clearer signal of our determination to secure a sustainable future for the world-class journalism we produce than the commitment we make today," said News UK chief executive Mike Darcey.
"This is a commitment by our company to London and the UK for the next three decades. Our titles will evolve, our relationships with our readers will strengthen and our mission to report, analyse and challenge the world will continue."
The Very Revd Andrew Nunn, Dean of Southwark, said: "We are delighted to welcome the staff of News UK to Southwark Cathedral for their carol service.
"2014 will be a big year for News UK as they move into their new headquarters alongside the Cathedral.
"As their neighbours and we look forward to working together for the good of the whole community and Christmas is a great place to begin that."
News UK has signalled that it will be launching a major programme of staff volunteering in Southwark.
Staff currently offer their time and skills to a range of community projects in Tower Hamlets, close to the company's current Wapping HQ, and this programme will be transferred to Southwark when the relocation of the business is complete.
News UK says it will work with Southwark community leaders to identify priorities when it is planning its programme of local activity.