Hugh Jackman took to Instagram on Wednesday to pay an emotional tribute to his late mother-in-law, Fay Duncan, who died Sunday, Aug. 28, at the age of 81.
"I'm blessed to say Fay Duncan was my Mother in Law," the 47-year-old actor wrote. "She was one of the greatest women I've ever met. Wise, funny, loving, cheeky, generous, and a true leader."
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"She had an incredible gift for always being right …. which must have been a true burden for her as she was also incredibly patient with us mere mortals," he continued. "Fay, I love you more than words can express."
On Thursday, Jackman and his wife, Deborra-Lee Furness, laid Duncan to rest in Toorak, Melbourne. During the memorial service, Jackman performed a touching rendition of "Quiet Please, There's a Lady on Stage," according to the Herald Sun.
Duncan was one of the driving forces behind the Fight Cancer Foundation. She spent 25 years developing, fundraising and implementing programs to help cancer patients and their families.
WATCH: Hugh Jackman Says Married Life 'Gets Better and Better'
The Wolverine star and Furness celebrated their 20th wedding anniversary earlier this year. The couple tied the knot on April 11, 1996 in Melbourne, Australia, after meeting on the set of the Aussie TV show, Corelli.
ET chatted with Jackman in February, where he gushed that married life "gets better and better" with each passing year.
"I was a very, very happy single man when I met my wife, and the moment I met her it was like 'this is 10 times better than my own life,'" he said. "It's just continued to be like that."
See more in the video below.