Katherine Schwarzenegger is constantly inspired by her mother Maria Shriver.

The 30-year-old author is currently preparing for the arrival of her first child with husband Chris Pratt, and Katherine has admitted to taking inspiration from her own mother.

In a heartfelt Instagram post on Sunday (10.05.20), Katherine - who has siblings Christina, 28, Patrick, 26, Joseph, 22, and Christopher, 22 - wrote: ''Happy Mother's Day to the greatest and most remarkable Mama in the entire world! We are the luckiest 4 kids in the entire world to have you as our mama. I am so beyond blessed to learn from you and you have made me want to be a mama for as long as I can remember. You mother not only us 4, but everyone you come in contact with. You are the Queen mother to all and I am so lucky to have you as my mom. I love you! [heart emoji] (sic)''

Meanwhile, Chris - who married Katherine in 2019 - previously predicted the author will make ''great'' mother.

The Hollywood actor - who has a seven-year-old son called Jack with ex-wife Anna Faris - said: ''She has changed my life for the better in so many ways. My heart, my soul, my son I feel are all so safe with her. She's a great step-mom. She's, God willing, going to be a great mom one day.

''She's got great parents, great siblings, she fills in all my many deficits. My nickname on these press tours is Yard Sale because I'm such a scatterbrain. And she doesn't mind helping me with that stuff. It's a good match.''

Katherine's father, movie star Arnold Schwarzenegger, also revealed he is ''looking forward'' to becoming a grandfather.

Speaking prior to their pregnancy announcement, he shared: ''It's up to Chris and her when they want to do that but I'm looking forward it to, yes.''