The co-founders of multi-billion photo-sharing giant Instagram, Kevin Systrom and Mike Krieger, are both leaving the firm.
In a statement released by Systrom, chief executive of Instagram, he said that that were departing to "explore our curiosity and creativity".
Instagram, which was purchased by Facebook in 2012 for $1bn (£760m) in cash and stock, now has more than one billion users.
Trouble in Paradise?
On the other hand, the exit comes amid reports of tension between Instagram's co-founders and Facebook's leadership.
Both Systrom and Krieger started the image sharing site in 2010, and continued to run the service after it was acquired by Facebook two years later.
According to the pair, they reportedly only told the Facebook leadership on Monday so the departure appears pretty sudden.
In a blog post, Systrom said: "We're now ready for our next chapter. Building new things requires that we step back, understand what inspires us and match that with what the world needs; that's what we plan to do."
There was no bitterness in the blog post. Systrom said the pair both remained "excited for the future of Instagram and Facebook".
However, CEO Mark Zuckerberg said in a statement that Instagram reflected the founders' "combined creative talents".
"I've learned a lot working with them for the past six years and have really enjoyed it," he said. "I'm looking forward to seeing what they build next."
Systrom and Krieger, who are both in their 30s, met while studying at Stanford University.
The two were inspired to create the Instagram app - originally launched just for iPhones in 2010 - by old Polaroid pictures.
Instagram had around 30 million users in 2012, the year it was purchased by Facebook for what appeared to be an eye-watering $1bn.
Before the purchase, the app was also ad-free. That changed. But so did the number of users - now more than a billion.
