Sanchez was seen sporting a large ring on her right hand as the couple boarded a yacht Sunday, the Daily Mail reported.
The pair, whose relationship was revealed in January, was then spotted cuddling on the boat at one point, taking in the sunshine alongside Russian-American businesswoman Dasha Zhukova.
The images surfaced after reports that Sanchez's divorce with Hollywood power player Patrick Whitesell was slated to be finalized by the end of October, freeing her up to marry the bachelor with a net worth of over $100 billion.
Bezos and ex-wife MacKenzie Bezos announced they were ending their 25-year marriage in January, shortly before the National Enquirer reported that Bezos and Sanchez were having an affair.
His ex-wife was awarded a 4 percent stake in the online shopping giant currently worth more than $36 billion, making her one of the top five richest women in the world and one of Amazon's largest shareholders. Meanwhile, Bezos retained a 12 percent stake worth around $114.8 billion and still remains one of the world's richest people despite the divorce, according to Bloomberg.
Bezos accused the National Enquirer of threatening to publish explicit photos of him unless he stopped investigating how the Enquirer obtained his private messages with Sanchez which were later revealed to have come from the brother of Sanchez, a person familiar with the matter told The Associated Press.
Sanchez is known for various roles in Hollywood including the 2004 film "The Day After Tomorrow" and the 2011 film "We Bought a Zoo" as well as her career as a news anchor and sports reporter. She also hosted Fox TV's "So You Think You Can Dance."
FOX Business' Matthew McNulty and The Associated Press contributed to this report.