Meghan Markle reportedly poised to release her own line of beauty products

Meghan Markle has been spotted visiting the estate of a major beauty marketing firm executive - and it could mean her own cosmetic line is in the works.

The Duchess of Sussex, 40, visited Guthy-Renker's co-founder Bill Guthy at his California home with Prince Harry and her mother Doria Raglan a few times early this year, reports The Sun.

The couple had also travelled on a private jet owned by the beauty firm during their recent New York tour, according to the Daily Mail.

It's led to increasing speculation that Meghan could be launching her own beauty line. It would be an incredibly lucrative move for the Duchess, following in the footsteps of the likes of Cindy Crawford, Kylie Jenner and Jennifer Lopez.

The couple were seen leaving Guthy's estate on March 1.

There's also been speculation that the Sussexes' controversial Oprah interview was filmed at Guthy's ranch.

The beauty executive is reportedly worth over $500 million - but his company Guthy-Renker has been fined for illegal business practices in the past.

The company had to pay out $26 million in a class-action lawsuit from customers who alleged its shampoo products caused hair loss. Meanwhile, ads for its acne treatment brand Proactiv were banned in the UK after being found to be "misleading".

Meghan could be launching her own beauty line. Photo / Getty Images

It comes as the royal family brace themselves for another attack from Harry, who is bringing out a new book. The Duke of Sussex has a $28 million advance from publishers. Royal experts believe he is under pressure to identify the royal family member who allegedly made racist remarks about the colour of baby Archie's skin.

It's understood Harry has been making contact with Princess Diana's old friends while researching for the book.

It was originally thought he would leave most of the work to a ghostwriter, but sources are "surprised" at how involved he has become in the process.