Meghan, Duchess of Sussex has become an investor in a female-owned premium coffee start-up brand.

The former Suits star, who is married to Britain's Prince Harry, has given Clevr Blends a big boost after connecting with co-founder and CEO Hannah Mendoza, and is backing the health-conscious brand, which debuted its instant oat milk latte line in 2017.

"This investment is in support of a passionate female entrepreneur who prioritizes building community alongside her business," reads a statement from Meghan to New York Post's Page Six.

"I'm proud to invest in Hannah's commitment to sourcing ethical ingredients and creating a product that I personally love and has a holistic approach to wellness. I believe in her and I believe in her company."

It's unclear how much she invested in Clevr, which is based in Montecito, California - the same neighbourhood Meghan, Harry and their son Archie call home - but the firm's affiliation to the Duchess has already paid off after Oprah Winfrey raved about their products in a video shared on social media.

The media mogul took to Instagram late on Sunday to show off a festive gift basket she had received from her royal neighbour, packed with packets of Clevr's SuperLattes.

"On the first day of Christmas my neighbour 'M' sent to me...a basket of deliciousness!" Oprah captioned the footage. "My new drink of choice for the morning and night. Wish I had @clevrblends sooner cause I would've added it to my Favorite Things (gift recommendation) list. #HappyHolidays".

Hours after Oprah's video was posted, Meghan announced her investment via Fortune magazine.