Jeff Bezos and Lauren Sanchez are reportedly already married.
The Amazon founder, 60, and his fiancee, 65, are in Venice where it was reported they were due to get married between Thursday and Saturday.
However, it's believed the extravagant Italian party is simply a celebration, and the couple made their union official last month.
"They have been married for at least a month, more than a month," a source told the Daily Mail. "The marriage is fully legal and took place in America under American law."
The source added, "When they were planning the wedding, they were clear about the fact that they were already secretly married. Whatever happens at the wedding on Friday, it will not be a wedding. Under Italian law, it will not be a wedding celebration, any vows said or rings exchanged will have no legal meaning."
It's also believed the couple has signed a pre-nuptial agreement to protect Jeff's $244 billion (£177 billion) fortune.
The couple's celebration service will take place at the hall of the Arsenale, a sprawling 14th-century complex in the eastern Castello district of Venice. Guests have started arriving, with celebrities including Kim Kardashian, Oprah, Orlando Bloom and Queen Rania of Jordan all spotted in the area.
Jeff and Lauren got engaged in 2023, four years after he split with his wife of 25 years, Mackenzie Scott. Lauren was previously married to Hollywood agent, Patrick Whitesell, when she met Jeff met in 2018. There are conflicting reports about whether the pair had an affair while they were both married.