Thomas Markle Jr. was seen by staff at Sydney Airport on Thursday before being quarantined, where he will remain for 14 days.
His arrival in the country comes just days after another Big Brother contestant, Katie Hopkins, was evicted for breaking quarantine rules.
A Channel Seven spokesperson told Daily Mail Australia: “We are not commenting on speculation about the cast of Big Brother VIP.”
“All will be revealed soon and Big Brother can’t wait to meet the new housemates.”
It is unclear whether Markle Jr, the Duchess of Sussex’s paternal older half-brother, is replacing celebrity commentator Hopkins, who was sent to the UK on Monday.
Hopkins, 46, sparked a national outcry when she boasted on Instagram that she tried to break quarantine rules by opening her hotel door without gloves and not wearing a mask when talking to hotel staff.
The celebrity, known for her extreme views on immigration and COVID-19, had her visa revoked on Sunday and was placed on a flight to Britain the following morning.
Other celebrity contestants taking part in Big Brother VIP include Caitlyn Jenner, who flew in from Los Angeles last week and is in hotel quarantine.
Jenner, 71, who is running for Governor of California, will reportedly receive a $500,000 bonus for her appearance on the show.
Markle Jr’s salary is unknown.
Meanwhile, Markle Jr. is likely to have obtained a ‘critical skills’ visa in order to be allowed entry into Australia during the COVID-19 pandemic, while thousands of Australian diaspora citizens remain stranded overseas and unable to return home.
This visa is granted when there is a clear economic benefit in allowing the person to enter the country.
“It is important to note that Channel Seven ensures that the arrival of international artists in Australia does not impact or prevent Australians from returning home from overseas,” a Seven spokesperson said.
“Every international artist associated with Channel Seven is on agreements that exist outside the flight limit on international arrivals and have been granted exemption by the government to come here. All our artists also undertake quarantine measures in accordance with government legislation,” the spokesperson further said.