Justin Bieber and Selena Gomez
Justin Bieber and Selena Gomez REUTERS

Selena Gomez was reportedly worried former boyfriend Justin Bieber might have had given her a sexually transmitted disease (STD).

According to a Life & Style report, the 21-year-old Come And Get It singer was not only afraid that Bieber had been unfaithful to her, but also was scared that he gave her an infection.

"Selena has had issues with anxiety for a while," an insider allegedly said. "And she's still dealing with them. It started when Justin was cheating on her — one big breaking point was that she thought he gave her an STD and got tested."

This comes after reports emerged Gomez was admitted at The Meadows treatment centre in Wickenburg, Arizona.

Meanwhile, the former couple were seen together in January, riding Segways near Bieber's Calabasas home, a year after their highly publicised split.

The former Disney star has previously voiced her concern for the Baby hitmaker, who was been involved in a series of unfortunate incidents lately.

"Part of life and growing up are going through things that aren't comfortable - and you hope you come out the other side a stronger person," she told MailOnline at The Sundance Film Festival. "I will always care about Justin no matter what - my instinct after all we have been through is to protect him from any harm."

"Whatever he is going through I want him to come out of it stronger," she added.