Prince Harry is planning to propose to his Suits actress girlfriend Meghan Markle with a custom-made ring crafted from a bracelet which belonged to his late mother Princess Diana, according to reports.

Harry, 32, is believed to have commissioned royal jeweller Harry Collins to work on the £100,000 ($125,000) cushion set emerald and platinum sparkler.

"[It's] flashy but not ostentatious," a source told the Daily Star Sunday of the fifth in line to the British throne's intended design.

Harry and Meghan, 35, have been dating for a year with talk of wedding bells intensifying in recent months.

Breaking with the traditional two-year courtship for royal engagements, Harry is said to be keen to walk down the aisle with Meghan sooner rather than later so that his grandfather Prince Philip can be part of their big day.

The Duke of Edinburgh's health has been in decline in recent years with him admitted to hospital for two days earlier this week for an infection arising from a pre-existing condition.

In May it was announced that the 96-year-old is retiring from royal duties this autumn.

Meanwhile, Prince Harry recently confessed that he had considered quitting being a royal but had remained for his grandmother, Queen Elizabeth II.

He told the Mail on Sunday : "There was a time I felt I wanted out. But then I decided to stay in [The Firm] and work out a role for myself."

Prince Harry and Meghan Markle
Prince Harry is reportedly planning to propose to Suits actress Meghan Markle with a custom-made £100k ring Getty

Prince Charles' son has since dedicated himself to charity work including teaming up with the Duke and Duchess of Cambridge on mental health campaign Heads Together.

He explained: "We are incredibly passionate with our charities and they have been chosen because they are on the path shown to me by our mother. I love charity stuff and meeting people."

Princess Diana holds Prince Harry
The ring is believed to be crafted from a bracelet belonging to Prince Harry's late mother Princess Diana REUTERS