Facebook's director of marketing Randi Zuckerberg, sister of the social network's billionaire founder Mark Zuckerberg, is leaving her brother's company to start her own social media consulting firm.

Randi, who has been with Facebook for the last six years, said she feels it is the "perfect time" to move outside of Facebook to build a company focused on the "exciting trends underway in the media industry."

"I have decided my time at Facebook is coming to a close. When I think about the projects I am most proud of during my six years at the company, they all have one thing in common -- they revolve around the intersection of traditional media and social technology," she said.

Facebook confirmed the departure and in a statement said, "We can confirm Randi has decided to leave Facebook to start her own company. We are all grateful for her important service."

However, there was no direct comment from her brother. Randi plans to start her social media consulting firm 'RtoZ Media'.

"My goal is to launch my own innovative programming and work with media companies to develop their programming in new and more social ways. In attacking this challenge, Facebook will clearly be a central element in all of my projects," she said adding that she hopes to continue advising Facebook on media projects.

According to her resignation letter posted on the website 'AllThingsD', Randi said she has focussed on innovating and pushing the media industry forward by introducing new concepts around live, social, participatory viewing. "We have made incredible progress, but there is still much to be done and other ways I can affect change."

A prominent name in Silicon Valley, Randi has been on maternity leave for the last three months. She was recently nominated for an Emmy award in the category of live coverage of a current news event for her work on 'Facebook Live', a real-time news show she created and hosted for the company.