Emilio Garcia says the incident, which happened on the Spanish holiday island of Ibiza, was part of a campaign of harassment that also included fat-shaming him.
"Emilio should never have been put in a position of having to be in the vehicle with her while she had sex with another woman," said Garcia's lawyer Ron Zambrano.
"'Inappropriate' is putting it lightly. Exposing this behavior to employees is definitely illegal."
The suit alleges the incident took place in June of 2022 when Garcia, who worked as a personal photographer to the star, was on tour with her.
"Plaintiff could not get out of the car as it was both moving and he was in the middle of nowhere in a foreign country," says the suit, filed Tuesday in Los Angeles Superior Court.
"Plaintiff was embarrassed, mortified and offended throughout the whole ordeal."
The "Hot Girl Summer" artist told Garcia not to talk about what he had seen, says the suit, which also claims she would tell him he was fat and ate too much.
Garcia's suit says the 29-year-old star began employing him in 2018, but classified him as an independent contractor, rather than an employee.
That meant he was not eligible for benefits such as health care or overtime pay, which could have run into the six figures.
The suit claims Garcia was contracted to work eight-hour days, but was required to take calls from Megan Thee Stallion, whose real name is Megan Pete, outside those times and to perform other tasks without being given proper breaks.
The suit, which alleges retaliation and multiple state Labor Code violations names as defendants Megan Thee Stallion, Megan Thee Stallion Entertainment, Inc., Hot Girl Touring LLC, and Roc Nation.
Garcia is seeking unspecified compensatory and punitive damages.
"Megan just needs to pay our client what he's due, own up to her behavior and quit this sort of sexual harassment and fat shaming conduct," said Zambrano.
Entertainment outlet Page Six cited Megan Thee Stallion's lawyer Alex Spiro as denying the allegations.
"This is an employment claim for money -- with no sexual harassment claim filed and with salacious accusations to attempt to embarrass her," the lawyer told the outlet.
"We will deal with this in court."
Last year, Canadian rapper Tory Lanez was jailed for 10 years in prison for shooting Megan Thee Stallion in the feet during a drunken argument after a Hollywood party.
