Bieber is due to sing at the Saudi Arabian Grand Prix on December 5 in Jiddah but Hatice Cengiz thinks it would send a strong message to the country's regime if he backed out.
Cengiz wrote in an open letter published in the Washington Post: "Do not sing for the murderers of my beloved Jamal.
"Please speak out and condemn his killer, Mohammed bin Salman. Your voice will be heard by millions.
"If you refuse to be a pawn of MBS, your message will be loud and clear: I do not perform for dictators. I choose justice and freedom over money," she continued.
Khashoggi was murdered and dismembered after entering the Saudi consulate in Istanbul in 2018.
The killing was carried out by 15 Saudi government agents who had been sent to Istanbul, where the writer and former government spokesman had an appointment at the Saudi consulate for documents needed to marry Cengiz.
Mariah Carey was the biggest-name performer to hit the stage in Saudi Arabia after Khashoggi’s killing by Saudi agents in Turkey in October 2018. She brushed off calls to boycott the show.
Public pressure, however, prompted Nicki Minaj in 2019 to cancel her appearance on stage at a concert in Jiddah, saying she wanted to show support for women’s rights, gay rights and freedom of expression.
Crown Prince Mohammed has maintained he had no prior knowledge of the operation that killed Khashoggi. A US intelligence assessment made public under US President Joe Biden, however, determined the crown prince approved the operation.
“Please know that your invitation to participate in a concert in Jiddah comes directly from MBS, as the crown prince is known,” Cengiz wrote in her open letter to Bieber.
“Nothing of significance happens in Saudi Arabia without his consent, and certainly not an event as important and flashy as this.”
Human Rights Watch has also called on Bieber and the other performers to pull out of the F1 concerts in Saudi Arabia, saying these events are aimed at “sportwashing” by diverting attention and deflecting scrutiny from Saudi Arabia’s human rights record.