The poorly timed joke, told while he addressed the Future Investment Initiative forum in Riyadh, referred to allegations that Lebanon’s premier-designate Saad Hariri was detained in the kingdom last year.
This week Hariri publicly backed the Saudis as they faced heat over Khashoggi’s murder.
Last November, Hariri mysteriously resigned in a televised address from the Saudi capital, sparking rumours he had been forced to do it.
Crown Prince Mohammed bin Salman was sitting beside Hariri when he quipped that he “will be staying in the kingdom for two more days, so I hope there are no rumours of his abduction,” before bursting into laughter and shaking Hariri’s hand.
Hariri smiled and offered a wave to the audience who heavily applauded the Crown Prince’s joke.
Saudi Arabia has long been a key ally of Hariri, while Riyadh’s regional foe Iran backs Lebanese Shiite movement Hezbollah.
A month after his resignatoin, after French mediation and the Saudis denying they had intimidating him into quitting, Hariri rescinded his resignation.
He was named premier for a third term in May after Lebanon’s first parliamentary elections in nine years, but has since struggled to form a cabinet.
Hariri, a dual Saudi citizen, has supported the Crown Prince and the Saudi leader’s stance on Khashoggi, who was brutally murdered inside the kingdom’s consulate in Instanbul on October 2.
“The measures taken by the Kingdom of Saudi Arabia regarding the case of journalist Jamal Khashoggi … come within the framework that serves the path of justice and the disclosure of the whole truth,” a statement from Hariri’s office quoted him as saying.
During the conference the Crown Prince vowed to bring the killers of Khashoggi to justice, describing the case as “painful, horrible and unjustified” in his first public speech since the start of the crisis.
“Saudi Arabia is taking all legal measures … and working with the Turkish government to reach results and bring all the criminals to justice,” the 33-year-old said.
“Justice will prevail.”
Prince Mohammed said some people were trying to make use of Khashoggi’s case to “drive a wedge between Saudi Arabia and Turkey.”