Diana's niece spotted in lavish 'engagement' ring weeks before sharing plans to wed

Princess Diana's niece was spotted wearing a diamond encrusted ring weeks before sharing to marry her fashion tycoon fiance.

Lady Kitty Spencer was pictured wearing the lavish band on her engagement finger in November while out in Chelsea in London.

The photos were snapped weeks before it was revealed that the 29-year-old was to wed South African-born multi-millionaire Michael Lewis, who turns 61 this month.

But it's not the first time Lady Kitty has been spotted wearing a ring on her engagement finger after she was seen with a large diamond in June and then again in August.

Lady Kitty is the daughter of Diana's younger brother, Earl Spencer, who is five years younger than his future son-in-law.

She was wearing a diamond ring (MJ-Pictures.com)

The groom is a South African-born fashion magnate with an estimated net worth of £80million.

He is said to have three children aged in their 30s.

Kitty and Mr Lewis went public with their relationship in New York City and were later spotted kissing after leaving a club in St Tropez, France, last August.

She reportedly went to the hairdresser in Chelsea (MJ-Pictures.com)

Lady Kitty is a fashion model (MJ-Pictures.com)

One of Lady Kitty's friends told the Daily Mail that Mr Lewis proposed to her before Christmas.

"She’s been in Cape Town for the holidays and told her mother and the rest of the family," the friend added.

"Michael is loved by all of them.

She was wearing a long black coat and black shoes (MJ-Pictures.com)

"Despite his wealth, he’s very humble and low key."

Lady Kitty went public with Mr Lewis after her previous relationship with Italian property magnate Niccolo Barattieri di San Pietro ended.

Lady Kitty and Michael Lewis are going to get married (BACKGRID)

Lady Kitty was spotted with a different ring when walking the red carpet at the Venice Film Festival in August.

She showed the ring while touching her hair as she wore a black dress.

Lady Kitty was born in England but grew up in Cape Town.

Lady Kitty was wearing a different ring during the Venice Film Festival in August (WireImage)

Lady Kitty with the ring in Venice (Getty Images)

She now works as a fashion model after studying for an Art History degree in Italy.

Lady Kitty is the daughter of the former British model Victoria Aitken and Earl Spencer, the younger brother of Princess Diana.

This makes her a first cousin of Princes William and Harry.

After her parents split in 1997, she divided her time between her father's home in England and her mum's in South Africa.