Former UK deputy prime minister Nick Clegg will take up a senior post at global social media giant Facebook.
In a move that took the UK political world by surprise, the ex-Liberal Democrat leader was named as the firm's head of global affairs and communications.
Writing on the platform, Mr Clegg said it was "an exciting new adventure" and he would move to the US with his family in January to work at the Menlo Park headquarters in California's Silicon Valley.
It comes as Mark Zuckerberg seeks to repair the company's reputation in the face of rows over transparency and the role of "fake news" on the platform after the 2016 EU referendum and the 2017 election of Donald Trump as US president.
UK Labour minister Jon Trickett said it was "a damning indictment of the sorry state of our country's politics" that Mr Clegg was becoming a lobbyist for the firm while it is under investigation both in the UK and by the European Union.
Writing on Facebook, Mr Clegg said the firm and its apps, including WhatsApp and Instagram, were "at the heart of some of the most complex and difficult questions we face as a society" over individual privacy, democratic integrity, the balance between free speech and prohibition online, artificial intelligence and the wellbeing of children.
He added: "I believe that Facebook must continue to play a role in finding answers to those questions - not by acting alone in Silicon Valley but by working with people, organisations, governments and regulators around the world to ensure that technology is a force for good.
"I am looking forward to being part of this endeavour."
It is understood Mr Zuckerberg was personally involved in hiring Mr Clegg, who led the Liberal Democrats from 2007 to 2015, including through five years in the coalition government with the Tories.
Mr Clegg is understood to be starting on Monday and will work from London until January, replacing Elliot Schrage, who did the job for ten years and will remain as an adviser.
Mr Clegg, who lost his Sheffield Hallam seat to Labour's Jared O'Mara at the 2017 election, is the most senior politician from Europe to work for Facebook.
He has not always been so keen on the firm, however, writing in a 2016 article for the Evening Standard that he was "not especially bedazzled" by Facebook.
"While I have good friends who work at the company, I actually find the messianic Californian new-worldy-touchy-feely culture of Facebook a little grating," he wrote.
"Nor am I sure that companies such as Facebook really pay all the tax they could - though that's as much the fault of governments who still haven't got their tax act together."
Last week, the business revealed new platform tools it says will increase transparency of political advertising as it faces investigations over the role of the adverts in elections around the world.
It is also facing a potential £1.2bn fine for a data breach that allowed hackers to access the personal information of 30 million users.
The Irish Data Protection Commission (IDPC), the lead supervising authority for Facebook in the EU, officially opened its investigation last week after the social media giant admitted hackers could have accessed the accounts of millions of users through a "vulnerability" on September 28.
Sheryl Sandberg, Facebook's chief operating officer, said Mr Clegg was "a thoughtful and gifted leader" who "understands deeply the responsibilities we have to people who use our service around the world".
In a Facebook post, she said: "Our company is on a critical journey. The challenges we face are serious and clear, and now more than ever we need new perspectives to help us though this time of change."