Facebook has appointed Nicola Mendelsohn as its European vice president, finally replacing Joanna Shields, who left the firm six months ago to lead the government's Tech City investment initiative.
Mendelsohn is one of the UK's most successful businesswomen and is currently the executive chairman at advertising agency Karmarama, which she joined in April 2008.
She said: "Facebook's innovation in the way brands are putting people at the centre of the conversation is fascinating. I am very excited to be joining the team and I look forward to bringing my experience to Facebook."
Mendelsohn has recently stepped down as president of the advertising industry trade body Institute of Practitioners in Advertising, where she was the first female president in its 96-year history. She has since been appointed the chair of the Creative Industries Council, a joint forum between the government and creative industries.
Mendelsohn will be based in London, reporting to Facebook's vice president of Global Marketing Solutions, Carolyn Everson. The firm could not confirm her official start date, although said it was likely to be mid-June.
Everson said she was thrilled with the appointment of Mendelsohn: "She brings outstanding leadership and passion for what Facebook can do to become an indispensable partner for our clients and agencies throughout the region. It's testament to Facebook's innovative role in business and advertising that we're able to welcome a leader with such great experience."
Mendelsohn, a mother of four, will be working a four-day week with Facebook. Such a decision spurs the debate currently circulating the tech industry on how whether women should be entitled to flexible working arrangements and part-time work.
With the industry being traditionally male dominated and fast paced, Mendelsohn's decision will be welcome by those critical of Yahoo boss Marissa Meyer, who recently banned employees from working from home, a policy seen as an affront to working mothers.
Facebook's chief operating officer Sheryl Sandberg recently wrote a book encouraging women to adopt the same pace as men in the workplace.