Jenna Bush Hager celebrating her 39th birthday on Wednesday meant it was also a special day for her "partner since birth."
The co-host of TODAY with Hoda & Jenna wished her twin sister, Barbara, a happy birthday on Instagram by posting a photo of them as babies and a series of shots of them growing up, along with a sweet message on the day they both entered the final year of their thirties.
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"Happy birthday to my partner since birth," she wrote. "I don’t know life without this beautiful, giving gorgeous soul — and wouldn’t want to. I’m the luckiest to be born walking through life side-by-side with the small girl with the largest heart. I adore you @barbaritabush!"
Barbara also got her chance to wish her twin sister a happy birthday when she joined a host of family and friends celebrating Jenna's special day with messages of love and gratitude on TODAY Wednesday.
"Happy birthday, sissy," Barbara said. "There is no one in the world that I would rather share a birthday with."
Barbara also talked about Jenna as a "very hilarious" child and what it was like growing up with her.
"Jenna concocted these wild worlds that our Barbies lived in," she said. "As a teenager, we shared a car, shared friends. ... The thing that I love most about Jenna is how much joy she brings to the world. ... I hope that this is your happiest year yet!"
The siblings' bond has also been the subject of a pair of best-selling books, including their first children's book, "Sisters First," which was released a year ago this month. Their first book, "Sisters First: Stories from Our Wild and Wonderful Life," detailed their time growing up in the spotlight as the daughters of former President George W. Bush.
Jenna expanded on the special relationship she shares with her sister in her most recent book, "Everything Beautiful in Its Time," which includes the toast Jenna made to Barbara at her sister's 2018 wedding to Craig Coyne in an intimate ceremony at the family's compound in Kennebunkport, Maine.
"As I did, I looked in her eyes and realized that my earliest, greatest love — the person who taught me the most about being in a partnership — had been just down the hall of our three-bedroom ranch house growing up: my sister, with her narrow shoulders, tortoiseshell glasses, and thick-as-rope auburn hair," she wrote.
"Barbara, I have loved you every moment of our lives," she said in her toast. "Having you as my life partner has been one of the greatest gifts of my life."