The model told Yahoo OMG that she has been appalled by jokes made at Kim's expense on social media and US comedy shows.
"I think Kim Kardashian looks so beautiful," Aldridge insisted.
"She is a beautiful pregnant lady and it's how you are supposed to look. I think people are crazy. It's ridiculous what people are saying about her."
Kardashian is expected to give birth to her and partner Kanye West's first child this summer.
Kim was also recently defended by her sister Khloe Kardashian, who described the Keeping Up with the Kardashians star as "truly magnificent".
Aldridge welcomed her own daughter named Dixie Pearl with Kings of Leon's Caleb Followill last June.
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