Cooper, 30, proposed to longtime girlfriend Scarlett Byrne in 2015 before tying the knot four months later.
Hugh Hefner's youngest son Cooper and his wife Scarlett Byrne have welcomed twin girls.
The Harry Potter actress shared the good news with her followers on her Instagram on Tuesday.
Cooper, 30, proposed to longtime girlfriend Scarlett in 2015 before tying the knot four months later. Reportedly, the couple welcomed their first daughter, Betsy Rose, in the same year.
Updating fans on their new arrival, mother Scarlett wrote on social media: "'My heart doubles this weekend to Cooper and I welcomed our daughters, Marigold Adele Hefner and Blossom Pearl Hefner, into the world.
"Our home is full of love with our three daughters and we couldn't be happier."
As reported in The Mirror, Cooper also took to Instagram to share the news of the new arrival, writing, "How blessed we are to be given the gift of his life. How lucky we are to have been given this love."
At the time their first daughter was born, they shared a statement: "We are overwhelmed with joy to share that our daughter, Betsy Rose Hefner, has arrived.
"We look forward to staying home and spending time together as a family in the days and weeks ahead."
He announced that he was joining his family in November last year.
"Scarlett and I will welcome two new family members this spring. We couldn't be happier as we await the arrival of our twins," Cooper captioned, 'Thank you very much everyone!'
Their first daughter Betsy was named after Cooper's late grandmother Betsy Aldridge-Conrad, who passed away in July 2020.
He shared, "My grandmother meant the world to both Scarlett and I."
Cooper, following in his father's footsteps, joined the family company at the age of 21 and later became Head of Global Partnerships and Chief Creative Officer of Playboy Enterprises.
Cooper's late father has recently come under fire after former Playboy bunnies Karissa and Christina Shannon revealed grim details of their bedtime ritual to the Daily Mirror.
He moved in with Hefner and his girlfriends and was paid $1,000 a week to star in the hit reality show Girls Next Door, which documented the lives of women living in a $100 million mansion.
Christina said she was routinely given drugs as part of Hefner's bizarre bedtime routine, before she was forced to have group sex with a pensioner and a group of other women.