Kristin announced yesterday that she is expecting another child with her NFL star husband Jay Cutler and Heidi was one of the first to send her well-wishes via Twitter.
In an oops moment, Heidi made a slight mistake, congratulating Kristin on the impending arrival of a baby boy, when Kristin actually doesn't know the sex of the child.
Heidi tweeted at Kristin: "CONGRATULATIONS on having another boy! You must be thrilled!!!!!! So excited for you and Jay! Sending my love to your family!"
Kristin, who is already mum to one-year-old son Camden, replied: "Lol...@heidimontag jumped the gun...we don't know the sex ;)."
Heidi responded: "Ha I guess not another boy, another a baby! Oops! Super exciting either way!"
Former Hills and Laguna Beach star Kristin announced her pregnancy via Twitter on Wednesday afternoon (30 October), after several US publications cited sources confirming the happy news.
Kristin wrote: "Thank you for all the love!! We are so excited for Camden to be a big brother!"
The 26-year-old married Chicago Bears player Jay in a small ceremony in Nashville in June 2013 and later honeymooned in Italy.
Their first son Camden Jack was born in August 2012.
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