Instagram is now the world's second largest social network, having grown to over 400 million users, surpassing rival Twitter with 316 million users monthly.
The popular photo and video-sharing app announced through its blog the new milestone it has reached merely nine months after hitting the 300 million user mark in December 2014.
"We are thrilled to announce that the Instagram community has grown to more than 400 million strong. While milestones like this are important, what really excites us is the way that visual communication makes the world feel a little bit smaller to every one of us," the company said.
In the blog post, Instagram also revealed that among the notable names who have joined Instagram within the past nine months include TV personality Caitlyn Jenner, English footballer David Beckham, German soccer player Toni Kroos and South Korea's idol T.O.P.
Welcoming the newcomers, Instagram revealed that more than half of the last 100 million to join live in Europe and Asia. In particular, countries with the most new Instagrammers include Brazil, Japan and Indonesia.
This milestone helped Instagram overtake Twitter to become the second biggest social network, next only to its parent company, Facebook. Mark Zuckerberg's social networking site now boasts of 1.3 billion active users, with its other famous apps WhatsApp and Facebook Messenger catering to 900 million and 700 million users, respectively.
In a Facebook post, Zuckerberg congratulated Instagram creators Kevin Systrom and Mike Krieger for reaching the 400 million people milestone. He wrote, "Congrats to Kevin, Mike and the entire Instagram community on reaching another big milestone."
Sharing a photo of him and Systrom walking and talking together, the 31-year-old Internet mogul added that he is "excited for the journey ahead."
Instagram has enjoyed constant growth since it was launched in 2010 as a free mobile service app. It was eventually acquired by Facebook in 2012.
The app, which allows users to easily take photos and videos and share them on social network platforms like Facebook, Twitter and Flickr, quickly gained popularity among celebrities, young adults and professionals. Among the famous personalities who constantly use Instagram include reality stars like the Kardashian-Jenner clan and Hollywood singers, such as Taylor Swift and Justin Bieber, among others.