On Oct. 10, Duchess Kate made her first public appearance since announcing she and Prince William are expecting their third child together. She attended an event in support of World Mental Health Day at Buckingham Palace in London and looked stunning in a light blue lace Temperley dress.

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Kensington Palace's Instagram page shared a photo from the event, and immediately, the 35 year old was criticized for her slender frame.

"Really, Is she pregnant?" one user wrote. Another compared herself to the royal, writing, "She is further along then me in pregnancy and she looks stunning and I'm over here looking like a cow."

While Kate has not announced her due date, it is believed that she will give birth in March or April 2018.

(She was forced to announce her pregnancy six weeks ago -- before the end of her first trimester -- because of the severe morning sickness from which she suffers.)

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Still, others praised the expectant mom for making the important appearance while she isn't feeling her best, with one person writing, "Thumbs up on the initiative but more importantly looking so composed and well with really rough morning sickness!"

One royal aide confirmed that Kate was in fact feeling poorly during the event: "The Duchess' condition is improving but she is still suffering from hyperemesis gravidarum," said the aide. "She is delighted to be able to be here tonight."

Stephen Fry, president of mental health charity Mind, also appreciated her presence at the event.

"I do understand she's been having this problem more severely than many pregnant mothers and so we're very grateful [she's here]," he said.

This is not the first time Kate has been shamed for her slim figure during pregnancy. She faced the same intense criticism while she was pregnant with both Prince George and Princess Charlotte.