Selena Gomez has posted a touching anti-bullying message on her Instagram page.

The 23-year-old singer previously admitted she was not popular at school and it was only having a cousin on the cheerleading team which prevented her from being bullied herself.

So as many of her fans prepare to return to school after the summer holidays, Selena decided to do her bit to stop bullying by sharing the post.

The message read: “Special request to all you kids returning to school in August. If you see someone who is struggling to make friends or being bullied because he/she doesn't have many friends or because they are shy or not as pretty or not dressed in the most 'in' clothes - PLEASE step up.

“Say hi or at least smile at them in the hallway. You never know what that person might be facing outside of school. Your kindness might just make a BIG difference in someone's life. Parents and grandparents should re-post this.”

In an interview with the Disney Channel back in 2012, Selena admitted she struggled to be accepted during this phase of her life.

“I was never the popular kid at school,” she said. “I had two friends, but I just sat at the back of the room and got on with my work.

“School is such an awkward time in your life. I was never confident in school.”

Selena also hit out at one of her Instagram followers who left a “distasteful” comment about cancer on one of her pictures in July.

“The comment you left about cancer was absurd. How distasteful of young woman,” she wrote. “I have gone through that battle with fans and family members. You can dislike someone but to wish something that could happen to you or your family is uncalled for sweetheart.”