Hugh Hefner's Son Cooper Engaged to 'Harry Potter' Actress Scarlett Byrne

Congrats Coop!

Cooper Hefner is officially off the market.

The 23-year-old son of Hugh Hefner and former Playmate of the Year Kimberley Conrad recently got engaged to 24-year-old actress Scarlett Byrne. Scarlett is best known for playing Pansy Parkinson in the Harry Potter franchise, and for her role as Nora on The Vampire Diaries.

Cooper proudly Instagrammed pics of Scarlett wearing a stunning yellow diamond ring on Wednesday, writing, "To many more adventures with this lovely lady @scarleybyrne."

NEWS: Cooper Hefner Bashes Holly Madison, Calls Her a 'Gold Digger'

"I was lucky enough to fall in love with my best friend," Scarlett also Instagrammed with a ring emoji.

Hugh, 89, tweeted out his congratulations to the couple on Thursday, writing, "Sending love and congratulations to my son Cooper and his fiancee Scarlett on their engagement!"

And Cooper reportedly handled his proposal the old fashioned way. He flew to London -- Scarlett's birthplace -- to ask her father for her hand in marriage, before popping the big question, Us Weekly reports.

The youngest son of Hugh recently stepped into his father's drama with his ex, Holly Madison, after the 35-year-old former Playboy Bunny made shocking claims in her new tell-all -- Down the Rabbit Hole: Curious Adventures and Cautionary Tales of a Former Playboy Bunny -- including that Hugh verbally abused her and offered her "thigh-opening drugs" when they first met.

"How does a person who is famous for being a gold digger paint themselves as a victim of a relationship they aggressively sought out for?" Cooper tweeted in June.

When ET sat down with Holly earlier that month, the former Girls Next Door star insisted she was not simply out for revenge by going public with her shocking claims.

"It wasn't about having an ax to grind or wanting to get a reaction from him [Hefner], or, you know, inviting him back into my life in any way," Holly said. "I don't really care about his response. I wanted to share my story to inspire other women who might be in a bad relationship to get out, or not be branded by bad decisions they've made, and take charge of their lives and move on. ... I'm definitely not rewriting history. I'm finally telling the truth of my experience."

NEWS: Hugh Hefner Responds to Holly Madison's Tell-All -- She Has 'Chosen to Rewrite History'

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