The singer, who has sported a goatee and backwards baseball cap for much of his public life, can be seen in the picture with longer, lighter-coloured hair and a handlebar moustache.
Durst, 50, deleted all previous images on his Instagram page, leaving only the one containing his new look.
“Thinking about you 70,” reads the enigmatic caption, alongside an emoji of a flying saucer.
His Instagram profile bio has also been updated to read: “You’re confused? Classic.”
Fans shared their reactions to his new look on social media, with one person writing: “This is an electric look, Fred.”
“Starsky and Hutch style,” wrote someone else, while another commented: “Well let me tell ya something brother. That’s a nice, HULKAMANIAC worthy moostaché.”
Others speculated that his “new hair” was in fact a wig.
“Fred Durst looks like he’s about to ask if you’ve ever heard of Neutral Milk Hotel,” joked one Twitter user.
“Fred Durst looks like he’s got into flipping houses on HGTV,” quipped another.
As well as being the frontman of Limp Bizkit, Durst is also known for writing and directing independent films.