""You've been makin' music for too long baby come cuddle me" - her," was the caption that accompanied the personal photo.
Justin, 19, had previously uploaded a photo of himself and Selena, 20, in an embrace that caused a stir amongst the couple's fans, but he swiftly deleted the image from his Twitter account.
Rumours of a reconciliation began last week when Selena flew out to Norway to spend time with Justin, who is currently in the middle of his Believe World Tour.
"They were holding hands, hugging and they kissed on the lips," revealed an onlooker. "They looked really in love. It definitely looked like they were back together," they concluded.
Justin and Selena called time on their relationship in November last year, citing their mutually busy work schedules as the reason for the split.
At the time Canadian-born Justin was busy on tour to promote his latest album and Selena was filming The Wizards Return: Alex versus Alex.
The pair first stepped out together in February 2011 at the Vanity Fair Oscar party.