The actor and voice coach Joan Washington, who he affectionately nicknamed 'the Colonel', were married for more than 35 years.
Writing in The Daily Mail, the 64-year-old revealed that the Prince of Wales had been one of her final visitors.
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"Prince Charles came to see 'The Colonel' last month, sat beside her, took her hand and said, 'It's been an absolute honour to have known you, Joan' to which she instantly quipped, 'I'm STILL here.' Which broke the ice and made all three of us cackle."
He added: "Astonishingly, unlike me, she's never been star struck and possessed the innate gift of speaking to everyone of any age or status as her equal."
In the moving tribute, Richard also revealed that the cause of his wife's death was stage four lung cancer which she had been diagnosed with two days before Christmas last year.
Richard and Joan were married for 35 years
Joan was well-known in the film industry and worked as a vocal and dialect coach for almost 40 years. Some of her high-profile clients and friends included Jessica Chastain, Anne Hathaway, Emma Stone and Vanessa Redgrave.
She and Richard married were married for 35 years and together, they shared one daughter, Olivia, and Joan's son, Tom. The couple met at the Actors Centre in London back in 1982 and struck up a romance after Joan agreed to give the Withnail and I star private vocal lessons. Richard then proposed to Joan at Heathrow airport, and the couple married soon after in 1986 at a registry office.
Joan sadly passed away on 2 September 2021 at the age of 71
Opening up about his proposal, he wrote: "I resolved to risk asking her to marry me, despite her avowed intention never to do so again. She met me at Heathrow Arrivals at 6.30am and I knelt on the luggage trolley, took out a ring and proposed. Which to my amazement, she accepted. Thirty-five years ago this November."
Richard broke the news of his wife's passing earlier this month by sharing a video of the pair dancing together to the song Only You. Alongside the clip, which was posted to Instagram and Twitter, he wrote: "ONLY YOU! Joan - Love of my Life & Giver of Life to our daughter Olivia."
He added: "Our hearts are broken with the loss of your Life last night. 35 years married & 38 together. To be truly known and seen by you, is your immeasurable gift. Do not forget us, sweet Monkee-mine."
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