The British royal first met the Suits actress in May (16) when he was in Toronto, Canada promoting the 2017 Invictus Games and he confirmed their relationship in November (16).
The couple's romance has since gone from strength to strength, with Harry having previously met Meghan's father, and now the redheaded prince is said to have introduced the actress to brother William's wife, The Duchess of Cambridge, and her 20-month-old daughter.
According to Us Weekly magazine, the meeting took place at Catherine and William's home, Apartment 1A in Kensington Palace, on 10 January (17).
"Meghan's so happy she's getting to know more of Harry's nearest and dearest," a source told the outlet, before adding the meeting "went well."
Catherine and Harry enjoy a close relationship, and are frequently pictured laughing together during official outings with other family members.
Britain's The Sun newspaper adds that Harry was keen to introduce Meghan to Catherine, because the duchess "really fulfils that older sister/maternal role" to him, following his mother Princess Diana's death in 1997.
"Kate was really looking forward to meeting Meghan and she knew how important it was to Harry. They are very close and he really values her opinion on girlfriends," a source told the publication.
"The meeting went really well and Meghan was very excited about meeting her."
William and Catherine's oldest child, three-year-old Prince George, is understood to have missed the meeting as he was at school. It is unclear whether or not William was present, but he first met Meghan two months ago, according to reports.
The family introduction came after Harry and Meghan are said to have seen in the New Year in Norway, where they reportedly enjoyed the local sights as well as watching the Northern Lights.
"Meghan's been on cloud nine since coming back from Norway," a source told Us Weekly previously. "Norway was amazing. It was the first time they had done something like this together, and they definitely want to go on more adventure trips… They're so in love."