Arnold Schwarzenegger's son Joseph congratulates Katherine on Chris Pratt wedding

Brotherly love! Arnold Schwarzenegger’s son Joseph Baena sent salutations to his half-sister Katherine Schwarzeneggeron her wedding to Chris Pratt.

His sweet message came after the Rock What You’ve Got author, 29, shared a gorgeous photo from her nuptials to the Guardians of the Galaxy star, 39, on Instagram on Sunday, June 9. “Yesterday was the best day of our lives! We became husband and wife in front of God, our families and those we love,” she captioned a picture of herself smiling up at her new husband. “It was intimate, moving and emotional.”

She added, “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.”

“Congratulations!” her 21-year-old half-brother responded, adding in a heart and champagne emoji.

The bodybuilder, who recreated his dad’s famous pose in January, was not in attendance at the Saturday, June 8, ceremony at San Ysidro Ranch in Montecito, California, which was kept small with roughly 60 guests. (Baena was spotted working out at the gym around the same time Katherine and the Avengers: Endgame star tied the knot on Saturday, June 8.)

The Total Recall actor fathered Baena with the family’s housekeeper, Mildred Baena, while still married to Maria Shriver. The couple, who split in 2011, share daughters Katherine and Christina, 27, and sons Patrick, 25, and Christopher 21.

Arnold opened up about his relationship with Joseph to Howard Stern in June 2015. “He’s terrific and he totally understands the situation,” he said. “So, it all has worked out. … It’s a very tough situation for him. It’s a very tough situation for my kids. Very tough situation for my family. It was tough for everybody. But it has happened and now we have to figure it out, right?”

Katherine and Pratt, meanwhile, who got engaged in January, started off their life together on the right foot: “Everything about the wedding was gorgeous,” a source told Us Weekly of the private affair. “They had beautiful weather and the perfect set up … Everyone seemed so happy and honored to be a part of the wedding and Chris and Katherine’s love story.”