The 26-year-old rapper -- who has a three-year-old son, King, with Chyna -- took to his former fiancee's Instagram on Friday to congratulate her on the news that she and her current fiance are expecting a baby.
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Meanwhile Kim, Khloe, and Kourtney Kardashian happen to be enjoying a Cuba vacation, which is somewhat similar to what happened during Chyna and Rob's engagement announcement a month ago, while most of the family was on a trip to Vail, Colorado.
This will be Rob's first child, and Chyna's second. Tyga is currently dating Rob's 18-year-old sister, Kylie Jenner.
This week, a source told ET that while Rob and Chyna's relationship was "tough for [Kylie] in the beginning," she's since gotten over it.
"She sees how happy he is and all she wants is for him to be happy," the source added. "The general consensus in the house is 'Praise Chyna! Don't go!' They finally got the brother they always knew back."