Pop star Usher has come out in defence of Justin Bieber, saying although the embattled superstar "hasn’t always chosen the path of his greatest potential," he is "not a racist."

Usher posted the statement on his Instagram account on Saturday in the wake of two videos in which Bieber uses the N-word and jokes about joining the Ku Klux Klan.

"As I have watched Justin Bieber navigate difficult waters as a young man, I can you tell you that he hasn't always chosen the path of his greatest potential, but he is unequivocally not a racist," Usher said on his Instagram account.

"What he was 5 years ago was a naïve child who did not understand the negative power and degradation that comes from playing with racial slurs."

The post was accompanied with an old photo of Usher with his arm over the now-20-year-old singer’s shoulder.

Bieber, who was discovered by talent agent Scooter Braun after he stumbled upon home videos of the singing sensation on the Internet, famously auditioned for Usher in Atlanta, Ga. In 2008, Bieber was catapulted to worldwide fame after signing a joint record deal with Usher and Braun's label Raymond Braun Media Group, and Island Records.

Earlier this week, Bieber issued an apology over Twitter after a video surfaced showing the then-15-year-old telling racing joke using the N-word.

A few days later, there were reports of a second, years-old video clip in which Bieber is also seen using the N-world and making references to the Ku Klux Klan.

In response, Bieber uploaded a photo of a Bible passage to his Instagram account that deals with forgiveness and salvation.

Celebrities rally around Bieber

Usher is not the only celebrity who has gone to bat for the pop sensation in the wake of the offensive videos. Rapper 50 Cent defended Bieber when he was asked about the controversial clips in an interview with U.K. newspaper The Sun.

"I just don’t think (Bieber) is racist," he said in the article published online on Friday.

"I don’t think he even knows who he is at this point – he's so young. When you see people become huge stars really early, it’s tough for them."

Professional boxer Floyd Mayweather has also spoken out about Bieber. In a Twitter post last Sunday, Mayweather highlighted the singer's age at the time of the incident.

Some of Bieber's fans, however, have been less forgiving. Following news of the videos, Bieber has faced huge backlash on social media.