In a comment posted on Katherine's photo from her and Pratt's big day, Baena wished the couple "Congratulations," and added heart emojis and a bottle of champagne emoji.
Baena is Schwarzenegger's son from a previously relationship he had with his former housekeeper, Mildred Baena.
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Yesterday was the best day of our lives! We became husband and wife in front of God, our families and those we love. It was intimate, moving and emotional. We feel so blessed to begin this new chapter of our lives. We are so thankful to our families and our friends who stood with us, and grateful to Mr Giorgio Armani, who created a once in a lifetime dress for me to wear, and for Chris, the perfect suit. This morning we feel nothing but blessed.
In addition to Baena, many other well-wishers have showered Katherine's comments with congratulations messages.
"This is the sweetest!!!! Congratulations you love birds. Wishing you a life of happiness," actress Gwyneth Paltrow said.
"Congrats and welcome to the club, married lady," singer and This Is Us star Mandy Moore added.
"You look flawless, but more importantly, so very happy! Congratulations, you two," Cupcakes and Cashmere CEO Emily Schuman wrote.
"So happy for you both! Felt like a perfect match when I met you both and could see the love and God in both of your energies for each other," author and former pro-footballer Lewis Howes stated. "The world is better because of this relationship. A healthy example of two people coming together to share more love."
Chris Pratt, 39, and Katherine Schwarzenegger, 29, tied the knot in a lavish ceremony in California— Lilian Chan (@bestgug) June 9, 2019
The nuptials took place at around 5.30 pm at the ultra-private San Ysidro Ranch in Montecito
Katherine oarrived at the marquee on the arm of her father, Arnold Schwarzenegger pic.twitter.com/MTmcWTG5vb
After the couple said their "I Do's," a source close to the situation told PEOPLE that Katherine was still experiencing a lot of emotions and was thrilled to be Pratt's wife.
“She’s still feeling emotional and overwhelmed by the weekend, in a good way," the insider told the celebrity news outlet. “She loves saying ‘husband'... She can’t believe how much her life has changed since meeting Chris.”