Aaron Carter on the road to recovery after mystery surgery

Singer Aaron Carter has assured fans he is OK after undergoing a mystery surgical procedure on Tuesday (01Aug17).

The former child star took to Twitter early on Tuesday to reveal it was "surgery time", although he did not share the nature of his medical issue.

A representative for Aaron later shared a photo of the musician from his hospital bed, posing alongside a nurse, and gave fans an update on his condition.

"From team AC, Aaron thanks all for the prayers and well wishes," read the message. "He's on his road to a beautiful recovery and journey ahead."

The operation appeared to be minor as Aaron was back on his feet on Tuesday afternoon, when he was spotted out in Los Angeles with his girlfriend.

The couple passed by celebrity spotters on the TMZ Tour bus, prompting Aaron to pull over his car and board the vehicle to greet the passengers.

"I just actually got out of surgery, but I just wanted to say hi to you guys," he told the tour guide.

Asked what he had been hospitalized for, he replied, "I can't discuss that right now, but I'm OK. Anaesthesia is no joke."

Making a quick exit from the bus, he told the group, "Take care and God bless."

The news of his surgery emerges days after Aaron revealed he suffers from a hiatal hernia stomach disorder, which makes him feel like an 80-year-old man.