"We couldn't be more excited," Sims wrote in a blog post. "I can't wait to meet our baby girl and I just know that Brooks is going to be the very best big brother ever. Two kids under three … here we GO!"
She also posted the news on Instagram with an adorable pic filled with pink balloons and the simple caption, "IT'S A GIRL!"
Recently, Sims, Vanessa Lachey, Rachel Zoe and Kerry Washington spoke with ET, where the moms and mothers-to-be shared their thoughts on pregnant supermodel Sarah Stage, who is barely showing despite being nearly nine months pregnant.