Sharing a happy snap of the couple embracing whilst Katherine – who is the daughter of Arnold Schwarzenegger and Maria Shriver – showed off her sparkling diamond ring, Chris wrote: 'Sweet Katherine, so happy you said yes! I'm thrilled to be marrying you. Proud to live boldly in faith with you. Here we go!'
And proving they’re still on friendly terms, Anna – with whom Chris shares six-year-old son, Jack – personally sent the couple a sweet congratulatory message.
'I’m so happy for you both!! Congratulations!' she wrote on the Guardian of the Galaxy star’s post.
Chris, 42 and Katherine, 29 confirmed their relationship in July 2018 have not yet announced a wedding date. However the actor did hint that they’d been keeping their surprise engagement news a secret for some time.
'Ideally we'd have kept this secret for as long as…,' he tweeted to his 6.6 million followers along with a link to his announcement on Instagram.