The 19-year-old entertainer, who has 12 millions followers on Instagram, is wearing a simple white T-shirt, gold chain and cap in the photograph as he poses with Smith.
“Me and uncle Will,” Bieber had captioned the picture, which was uploaded four months ago.
Instagram’s CEO Kevin Systrom said during an appearance on a show, that there are millions of photos shared every day, but Bieber’s photo with Smith garnered more than 1.5 million likes.
Instagram announced the news today along with other end-of-year roundups, including the most Instagrammed locations and hashtags.
Posted in August, the image features a casually-dressed Juju and Will Smith posing outside a house, with Smith making a sideways peace sign. Justin has some 12 million followers on the photo-sharing network and 1,168 posts to date.