Not long after, Schwarzenegger later took to the 'gram to share the same heartwarming image. She wrote, "My sweet love. Wouldn't want to live this life with anyone but you."
The pair first sparked rumors of romance back in June after they were photographed having a picnic. Pratt shares a 6-year-old son, Jack, with his ex-wife Anna Faris, who also congratulated the newly engaged couple. "I'm so happy for you both," she said on the couple's Instagram post. "Congratulations!"