Facebook Chief Product Officer Chris Cox (left) is leaving the social media company.
The move will more tightly integrate the three apps - a move that critics say could have potential antitrust implications and which reportedly has sparked disagreement among some of Facebook's senior employees.
In his blog post, Zuckerberg said that Cox had told him that he planned to move on several years ago, but that Cox chose to hold off on leaving until the company made more progress combating misinformation and Russian meddling - controversies that erupted in the wake of the 2016 election.
Chris Cox was put in charge of some of Facebook's most important features, including Instagram, Messenger, and WhatsApp - which together have over 2.7 billion users worldwide.
"It is with great sadness I share with you that after thirteen years, I've chose to leave the company", Cox wrote in his post. Considering WhatsApp is a platform already focused on privacy and being one of the only Facebook apps to have end-to-end encryption at this time, it's quite surprising to see Daniels leaving just a week after Facebook's privacy-focused announcement.
Cox's unexpected departure, which he and Zuckerberg announced in separate Facebook posts Thursday, comes months after Cox was promoted in a major reorganization.
Also, WhatsApp head Chris Daniels - who took over the chat platform last May - will be leaving the company, Zuckerberg said.
Fidji Simo, head of video, games and monetization, will be the new head of the Facebook app, Mark Zuckerberg said in a blogpost. The longtime Facebook executive Will Cathcart will head up WhatsApp. I'm deeply grateful for everything Chris Cox and Chris Daniels have done here, and I'm looking forward to working with Will and Fidji in their new roles as well as everyone who will be critical to achieving this vision.
Once again, Facebook's shift towards privacy is a big change at the company - both at a technical and cultural level. He also built Facebook's first human resources teams and oversaw the strategy for the apps that Facebook owns, Zuckerberg wrote.