The actress, 19, who plays Tiffany Butcher on the soap, said she thought it should be celebrated that she felt happy in her own skin.
She shared a video in which she is wearing a yellow cropped top and unbuttoned denim shorts on the social media platform.
But shortly afterwards, the actress posted a video on her Instagram story responding to comments.
She said: “I get a lot of comments saying that I’m vain and that I love myself, and you are absolutely right – I do love myself.
“And it’s taken me a while to feel this way so I’m so sorry if my happiness offends anyone because I’m just living my movie, I’m just living happily in my skin and I think that should be celebrated – not discouraged. Correct me if I’m wrong, guys.”
Smith reprised her role as the daughter of Bianca Jackson (Patsy Palmer) and Ricky Butcher (Sid Owen) in the soap in 2018.
She first joined the BBC One serial drama in 2008 at the age of six, but left the show in 2014 with her family when Bianca chose to start a new life in Milton Keynes.