The 62-year-old, who has two children with her husband Christopher Guest, shared the news with her child’s permission in the latest issue of AARP magazine.
The actress explained that she and her husband “have watched in wonder and pride as our son became our daughter Ruby.”
She added: “She and her fiancé will get married next year at a wedding that I will officiate.”
Ruby, 25, is a computer gaming editor, while Ruby’s older sister, Annie, 34, is a dance instructor.
Curtis told the magazine that she has no grandkids yet, “but I do hope to” in the future.
The actress opened up about how her daughter’s transition opened her eyes.
Meg Grant, who interviewed Curtis, explains in the article: “Possibly one of the biggest “old ideas” that Curtis has shed recently is the notion that gender is fixed.
“With her younger child’s permission, Curtis reveals that she and Guest ‘have watched in wonder and pride as our son became our daughter Ruby. And she and her fiancé will get married next year at a wedding that I will officiate.’
“Ruby, now 25, is a computer gaming editor. Older sister Annie, 34, is married and a dance instructor. Curtis says she has no grandchildren — ‘Not yet, but I do hope to.’
“Her life, these days, is what Curtis describes as a ‘constant metamorphosis.’”
Curtis is an award-winning actress and Hollywood royalty – as the daughter of Janet Leigh and Tony Curtis.
She made her film acting debut as Laurie Strode in John Carpenter’s horror film Halloween (1978), and went on to appear in the sequels.
She is also known for her work in cult comedies Trading Places (1983), for which she received a BAFTA for Best Supporting Actress, and A Fish Called Wanda (1988), for which she earned a BAFTA nomination for Best Actress.
More recently she starred in the cult films Freaky Friday (2003) and Knives Out (2019).
Curtis married her husband Christopher Guest in December 1984.
She reportedly saw a picture of him from the movie This Is Spinal Tap and told her friend “I’m going to marry that guy”, actually marrying him five months later.
The couple has two adopted children, Ruby and Annie.
In the article, Curtis opened up about being married to Guest since 1984 – calling him her “one and only.”
She said that, on a recent wedding anniversary, she wrote him a song with the lyrics, “I feel safe when I drive up and see that you are hope.”
Curtis explained: “That’s the long marriage. It’s the safety of knowing his car is in the garage, that I’m not alone, and that he’s here.”
She added that the two have no “big delusions of grandeur” about their relationship.
Curtis also opened up about being 22 years sober, saying she’d be ‘dead for sure’ if she hadn’t kicked her addiction.
The Halloween actress has openly spoken of her addiction to painkillers and alcohol and previously revealed that getting sober has been her ‘greatest accomplishment’.
In February, the Trading Places star celebrate her sobriety with fans in an Instagram post as she wrote: “A LONG time ago… In a galaxy far, far away… I was a young STAR at WAR with herself.
“I didn’t know it then. I chased everything. I kept it hidden. I was a sick as my secrets.
“With God’s grace and the support of MANY people who could relate to all the ‘feelings’ and a couple of sober angels…I’ve been able to stay sober, one day at a time, for 22 years.”
The actress will next appear in the upcoming Halloween Kills and its sequel Halloween Ends.
The movie is scheduled for an October 15, 2021 release.