On Wednesday, the 27-year-old tweeted congratulations to another Hills star, Kristen Cavallari, who recently announced that she was pregnant with her second child.
"CONGRATULATIONS on having another boy! You must be thrilled!!!!!! So excited for you and Jay! Sending my love to your family!" Montag wrote.
But Montag did get one detail wrong.
"Lol...@heidimontag jumped the gun...we don't know the sex ;)" Cavallari wrote back.
Ha, I guess not another boy, another baby!" Montag added. "Oops! Super exciting either way! xo."
Montag and her controversial husband, Spencer Pratt, were similarly friendly about ex-friend Lauren Conrad's recent engagement announcement. Though they lost touch after The Hills ended, Pratt recently told Life & Style that Lauren deserves to find happiness."
“We wish her all the best," he said.
"@LaurenConrad Congratulations on your engagement!!! so happy you found true love! I pray you have a long, happy, blessed marriage! xoxo!" Montag tweeted at the time.
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