The engaged couple was spotted entering a church in Santa Monica on Easter Sunday.
And they were all smiles as they chatted with other church- goers and posed for photographs.
The 39-year-old 'Guardians Of The Galaxy' star was also joined by his son Jack, six, whom he shares with his ex Anna Faris.
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The handsome actor cut a dapper figure in a navy sports coat and black pants as he held his adorable son's hand.
His 29-year-old fiancée wore a pink and white check romper as she kept warm with a white cardigan.
The couple was all smiles as they headed into church as little Jack clutched a cuddly toy and wore some cool shades to screen his eyes from the sun.
The couple is reportedly having a lot of fun planning their wedding together. A source revealed: "Katherine is having the best time planning everything. She loves it!"