The song is traditionally a highlight for his female fans as one lucky Belieber is brought on stage while the 19-year-old pop star sings the song to her.
At Bieber's Cape Town concert, teenager Neli was selected to be onstage while Bieber sang One Less Lonely Girl to her.
But on Mother's Day in Johannesburg on Sunday, Bieber gave his mom Pattie Mallette, 38, the special honour.
He posted on Twitter during the show:
Happy Mother's Day @pattiemallette . Today u r my #OLLG . Love u
— Justin Bieber (@justinbieber) May 12, 2013
Pattie shared her happiness at being specially chosen for the honour.
So yep.. @justinbieber surprised me for mother's day tonight & brought me out for OLLG!#verysweet
— Pattie Mallette (@pattiemallette) May 12, 2013
An estimated 75 000 fans – and their parents – descended on the FNB Stadium to see Bieber live in concert on his Believe world tour on Sunday.
The Canadian sensation had his young audience eating out of his hand as he danced his way through his hit songs like Beauty and the Beat, Boyfriend, As Long as You Love Me and Baby.
He also enjoyed a safari ahead of the Joburg concert, tweeting a wildlife photo:
#InTheWild instagram.com/p/ZISMAJgvkx/
— Justin Bieber (@justinbieber) May 10, 2013
Bieber will take a much-deserved break from his Believe tour after wrapping up his South African dates, and will resume his tour in California on 22 June.