Catherine Duchess of Cambridge's baby sister Pippa Middleton was spotted looking effortlessly stylish as she strolled the streets of London, England on Wednesday afternoon.

The Vanity Fair columnist and her boyfriend Nico Jackson have been the subject of engagement rumors as of lately but experts have revealed that the speculation isn't too far from the truth.

According to Just Jared, wedding expert Anne Chertoff told Glamour that she predicts the 30-year-old will have a ring on her finger sooner rather than later.

She said, "Pippa's been very intentional about keeping a low profile at the request of the royal family."

Adding, "Pippa and Nico have definitely talked about marriage. I can almost guarantee we'll see a ring on her finger before we see one on Cressida Bonas."

New reports are claiming that there is trouble in paradise for the blonde beauty and her boyfriend Prince Harry.

A source told E! News, "There is a growing feeling among a small section of them that Cressida isn't the perfect choice for him."

The source continued, "I don't think it's because there is anything wrong with the relationship or they don't like her, but there is concern that she is too much of a free spirit to be happy in the royal family long-term.

"They worry that she wouldn't be able to fully adapt to that lifestyle. They think she's too carefree and would find it difficult to live by the protocol that comes with the job, which of course it is. It might be too much of a constraint for her. And that could cause problems for everyone."

News of doubts on the romance comes on the heels of a report claiming that Prince Harry and girlfriend Bonas have been talking about marriage.

Last month an insider revealed, "Harry and Cressida have made a point of talking about marriage and what changes they're going to have to make to their life of late."

The source continued, "According to friends of Cressida's, the couple have decided to try and keep their semi normal lifestyle as long as physically possible."