AceShowbiz - "Mamma Mia!" star Amanda Seyfried has taken a top fashion influencer to task for showing off her post-baby bikini body online.

Arielle Charnas, a.k.a. Instagram's Something Navy, posted a beach-ready picture of herself with the caption, "Proud of my body after two kids" and it appears the image and the idea behind it really irked another mum, Amanda.

She reposted a comment a friend left on Charnas' popular page, and added the caption, "If we're ready to get paid for flaunting our lifestyle (and inspiring some in the meantime) we have to be open to the discussions surrounding what we're promoting."

"If you know who you are - take a second to decide if what you're throwing out there is worth it - in the big picture."

Charnas, who has since blocked the actress and her friend, has since addressed some of the negative responses her photo dredged up, revealing she felt "punished because I'm thin."

Seyfried was also attacked for appearing to criticise Charnas, responding by writing, "I'm sorry if this stinks of (judgment). It's not meant to. It's all a discussion that needs to be had."