Member's extended family have arrived in London ahead of the royal wedding.
Ms Markle's sister-in-law Tracy Dooley was pictured at Heathrow Airport with sons Tyler and Thomas.
Ms Dooley, who was married to the former actress's half-brother, has previously told ITV's Good Morning Britain she had not received an invitation to the ceremony at Windsor Castle on Saturday, admitting she had not seen Ms Markle for 20 years.
Just touched down in London!!! Man what a journey so far ?. We're safe and sound!
Her arrival in the UK comes amid speculation that Ms Markle's father, Thomas Markle, has pulled out of attending her marriage to Prince Harry, having been due to walk her down the aisle.
The Dooleys took to Facebook to announce their presence in the capital on Monday evening.
Ms Dooley posted pictures of landmarks, including the Palace of Westminster and the London Eye, writing: "We're here! Yay!"
Her son Tyler uploaded an image of the Imperial War Museum, as well as a photograph of the inside of a hotel room.
"Just touched down in London!!! Man what a journey so far," he wrote. "We're safe and sound!"