The "Guardians of the Galaxy" star proposed to Katherine, 29, on January 13 following a whirlwind romance. While her mother Maria Shriver took to social media to share her congratulations shortly after news broke of the engagement, "The Terminator" star Arnold waited to share his - and did so during an interview with U.S. TV show "Extra".
As host Mario Lopez congratulated Arnold on the news, the 71-year-old replied: "Thank you so much. That was really fantastic. She is so happy, they both are so happy. As I said to him, he is such a likeable guy. I love Chris - he's fantastic."
Back in November (2018), Arnold was spotted getting to know his daughter's new boyfriend as he and girlfriend Heather Milligan met the couple for breakfast in Santa Monica.
Following news of Chris and Katherine's engagement, a 2017 video interview with the lifestyle blogger emerged, with Katherine asked which famous Chris she liked the look of the most - Chris Hemsworth, Chris Evans or Chris Pratt.
While she first answered Chris Evans, Katherine then changed her answer to Chris Pratt - commenting that he's "been looking good lately".
"When she said Chris Evans, my heart sank and then she rescued it," Chris laughed, before questioning whether or not the video had been edited.
However, the interviewer assured him that it hadn't, replying: "No I swear, this is from two years ago. Talk about foreshadowing!".
Chris and Katherine's engagement comes after the screen star finalised his divorce from actress Anna Faris, with whom he shares six-year-old son Jack, last autumn.