"We're all healthy and happy," the 32-year-old captioned an Instagram photo of the newborn Sept. 27 with a sun emoji. "Andrew and I are so in love with our sun!"
Calling his delivery "the wildest experience," Bonnie continued, "So grateful for our birth team that have held our hands throughout and made the journey so joyous and expanding."
After tagging some of the "amazing" birth workers she consulted with before and during the delivery, the actress thanked her husband—who she married in March 2022—for being "my rock throughout birth quite literally as I squeezed onto you so tight and you never wavered."
"Elio has the most tender loving papa," she added, quipping, "Ok hormonal emotional extra long caption over!"
Needless to say, Bonnie's Harry Potter family descended upon the post's comments section faster than a snitch on the Quidditch pitch, with her onscreen brother James Phelps writing, "Huge congratulations!!"
Added Scarlett Byrne Hefner, who played Slytherin's Pansy Parkinson, "Congratulations!! Welcome Elio, he's beautiful."
Bonnie, who portrayed Ginny Weasley in all eight Harry Potter movies, is the latest Hogwarts alum to welcome the next wizarding generation. Her onscreen husband Daniel Radcliffe, whose titular character shares three kids with Ginny, became a dad this spring when his longtime girlfriend Erin Darke gave birth to their first baby together.
And just last year, Scarlett welcomed twins Marigold and Blossom with Hugh Hefner's son Cooper Hefner, while Jessie Cave—who played Lavender Brown—gave birth to her fourth child following a battle with COVID-19.
As for other Weasleys who now have real-life kids? Rupert Grint shares 3-year-old daughter Wednesday with actress Georgia Groome, while James' twin brother Oliver Phelps is a father to two daughters with wife Katy Humpage.