Aaron Carter. Picture: Instagram

Aaron Carter returned to Twitter over the weekend to reveal that he'd put 14kg in just three weeks.

The 29-year-old singer left rehab early last week after some unspecified "legal and personal matters" cropped up, but he certainly hasn't let his early release ruin his progress as he took to Twitter over the weekend to show off his healthy weight gain.

READ: Aaron Carter checks into treatment facility

Alongside a split image of his body before and after, he said:

He then added: "You need to let go of your fear and anxiety of being judged by others. You need to learn to accept yourself before anybody else will accept you."

Aaron's representatives announced on September 22 he had checked into rehab to "work on his overall wellness" after he admitted he was "concerned" about his health.

He said at the time: "I'm concerned about my overall health because people tell me I look like I have AIDs or I look like I have cancer or I look like I'm dying."

Fans feared the 'I Want Candy' hitmaker would return to his old ways after he was forced to leave the facility before his scheduled time at the beginning of October.

But his representative, Steve Honig, confidently explained: "Aaron has left the facility where he has been working on his wellness. Several legal and personal matters arose that required his immediate and in-person attention.

"He is still very much committed to his wellness and will be continually working toward being the best person possible."