The Hollywood star and author Schwarzenegger, the daughter of politician and actor Arnold, got married at the weekend.
Sharing the first image from their nuptials on Instagram, Pratt wrote: "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."
He continued: "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 Katherine to wear and for me, the perfect suit.
"This morning we feel nothing but blessed."
The couple - who are both Christians, announced their engagement in January.
Guardians Of The Galaxy star Pratt was previously married to actress Anna Faris. They have a six-year-old son, Jack.
Pratt has regularly shared his faith on social media and in interviews.
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