Cody Simpson was forced to reaffirm his sobriety as fans questioned his erratic behaviour online amid the coronavirus pandemic.

The Australian singer, who recently revealed that he's been sober ever since finding love with his new girlfriend, Miley Cyrus, has been self-isolating with the Wrecking Ball star.

However, after sharing a clip on Thursday in which he could be seen dancing energetically around his room, the star prompted concern that he'd relapsed.

"Day 6 & I’m finally starting to crack! #CORONAVIRUS," he captioned the post.

Taking to the comments, fans began to question whether he'd taken something to cope during the global health crisis, with one fan writing: "(On a) scale of 1 to 10 how sober are you?"

"DEAD SOBER believe it or not," he replied.

Speaking with InStyle Australia recently, Cody credited sober living with allowing him to be successful in so many different fields.

"Now I'm more interested in immersion and feeling good, sharp, open and clear. I found that being sober helps with that a lot," the star explained. "I can't say I'm going to do (sobriety) forever or even for the next year. It's just that right now it's what feels good."

The outbreak of Covid-19 has seen more than 258,000 cases of the virus registered, resulting in a death toll of over 10,500, since it began in December.

The World Health Organization (WHO) has advised people to practice social distancing and stay home in a bid to prevent the spread of the virus.