Post Malone is trying to ease fan concern over his noticeable weight loss ... he insists he's happy and healthy and nothing is amiss.
Post is on tour in Australia, and lots of folks became concerned when video showed him looking slimmer as he performed in a t-shirt and shorts. Many believed he was battling illness or even addiction because of his dramatic weight loss and the obscure movements he made while singing.
Sources close to Post tell TMZ ... there's no need for fans to be alarmed, because he's not on drugs or sick, in fact, it's quite the opposite.
Our sources say Post previously gained some weight for a movie role, but ever since he's been adhering to a strict diet and working out. Post's been touring since September, and he does a 90-minute set, and we're told that's contributing to the weight loss too.
In fact, Post Malone's dad even weighed in on his son's new look on social media ... leaving a comment on a fan video questioning Post's health due to his weight loss, saying ... "Healthiest he's been in years! Mentally and physically."