They're still the best of friends.
"When my cousin Sophia told me she was pregnant!" she captioned the Nov. 16 Instagram post. "The best news ever. love you @therealsophiagrace."
In the sweet clip, Sophia Grace shows her a picture on her phone before displaying her stomach, resulting in a shocked Rosie covering her mouth and repeating, "You're joking," to which Sophia says, "I knew she would cry." The video then cuts to the pair on a couch with Rosie rubbing Sophia's stomach as she applies lip gloss.
Sophia Grace announced on Oct. 22 that she had a little one on the way in an eight-minute YouTube video. And just a day after her cousin shared the news, Rosie exclusively told E! News what it was like when Sophia Grace told her—and showed off the sonogram—during a visit to their grandmother's house.
"I literally froze and then burst into tears and then Sophia showed me her scan picture," Rosie recalled on Oct. 23. "I'm so happy for Sophia. She has always been amazing with children and she's gonna be an amazing mum."
She added, "She also has a very supportive family around her to help and I'm gonna be there every step of the way! I can't wait to buy the baby loads of cute clothes."
As for Sophia Grace, she also reflected on sharing the news with Rosie, calling it, "literally one of the most happiest moments ever."
"She was just so happy because we've been so close our whole life and we literally have done everything together," the singer exclusively told E! News Oct. 29. "I'm going into a new chapter and obviously she's going to be the best cousin ever. I'm so excited for her to meet the baby."
For the latest breaking news updates, click here to download the E! News App