WATCH: HELLO! Insider: Harry and Meghan's Oprah Interview
The US TV show host asked Prince Harry how they were getting along after Harry admitted the pair weren't on speaking terms for a while, to which the Duke responded that there was "a lot to work through".
Harry added that he feels "really let down" since both he and Charles have been through something similar in losing a loved one, Princess Diana - Harry's mother and Prince Charles' late wife. But he added that Charles was now taking his son's telephone calls.
Nonetheless, the Duke went on to say that he will "always love" his dad and will continue to make healing their relationship "a priority", while referring to Charles' role as Harry's son Archie's grandfather.
The Sussexes were last pictured with the royal family at the 2020 Commonwealth Day service
The Duke also touched on his relationship with other family members during the two-hour primetime special. Of his brother, Prince William, he said that he "loved him to bits" and that they have "been through hell together". He added that they have a "shared experience" but that they are on different paths.
Prince Harry and his brother Prince William
Harry addressed rumours of a rift between himself and his brother William for the first time in Tom Bradby's 2019 documentary, Harry and Meghan: An African Journey.
When asked by the journalist at the time about the reports, the Duke said, "inevitably stuff happens" but that there was little truth to the speculation, adding: "The majority of the stuff is created out of nothing but as brothers, you know, you have good days, you have bad days."
Harry also noted William's importance in his life, saying in the documentary: "We are certainly on different paths at the moment, but I will always be there for him as I know he will always be there for me. We don't see each other as much as we used to because we are so busy, but I love him dearly."
Harry expressed his admiration for his grandmother, the Queen, too in Sunday night's interview, saying that he has a "deep respect" for her, and that they have spoken more in the past year than for many, many years.
The Duke and Duchess of Sussex stepped back from royal duties in March 2020 and moved to the US with their one-year-old son Archie.
The couple are expecting their second child in the coming months.
WHERE TO WATCH: In the US, the show was broadcast on Sunday evening on CBS. In the UK, CBS Presents Oprah with Meghan and Harry will be broadcast on Monday night at 9pm on ITV, and on ITV hub.
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