Samantha Grant, who has the same dad as Meghan, has seemingly deleted her public social media account.
A search for her account shows up an error page reading "sorry, that page doesn't exist!".
The sudden move comes after Daily Star Online revealed she is set to go to the Royal Wedding on May 19 – despite not being invited.
A source told us Samantha, 36, is being paid by a news organisation to fly 4,400 miles from her Florida home to be at Windsor Castle for the big day.
The source also said the half-sister, who suffers with multiple sclerosis, is likely “to start s**t” with her surprise appearance.
***Meghan's sister to GATECRASH Royal Wedding: 'She's going to stir up a S**T storm'***
The Twitter account she has deleted, under the handle @SamanthaMGrant, is the one she has used to fire off shocking rants at Meghan and Harry in recent months.
She most recently called Harry a hypocrite for “allowing Meg to ignore the Markles” and bizarrely told him to “man up”.