"Congratulations to my Family @blacchyna and @robkardashian!!!" Amber Instagrammed on Tuesday, re-posting Blac Chyna's pic of herself flashing the shiny piece of jewelry alongside Rob. "Pease don't let nothing or no one tear u guys apart! I never seen my sis so happy and I couldn't be more happy for her! Sometimes we find love in the strangest places Lol God Bless you 2!"
Amber, 32, also can't wait for their future children.
"Now let's get this wedding together so y'all can start making some babies #TrueLove #putaringonitsouknowitsreal #BlacRob," she added.
Jeweler Ben Baller -- whose celeb client list includes Rob's brother-in-law, Kanye West -- confirmed the engagement on Tuesday, posting this close-up video of the dazzling 7 carat ring on Instagram.
"Congrats to @RobKardashian & @BlacChyna on getting engaged. Rob, I have never seen you this happy before and I've known you since you were a teenager," Baller wrote. "I'm glad you came to your day 1 homie to get this massive [ring emoji] for your lady. You know I don't play when it comes to diamonds. God bless #7Carats #VVS #IFANDCO #BlacChyna #RobKardashian."
And the couple had no problem showing off Blac Chyna's new bling. Rob, 29, Instagrammed a pic of the 27-year-old model holding up her left hand, while she holds a stack of cash in the other.
Rob and Blac Chyna have been dating since January, and have since been inseparable. The once reclusive reality star declared his love for Blac Chyna last month in a now deleted Instagram post. "Love this woman right here, so f**k y'all with your negative comments!!" he wrote.
Amber dished about the two's relationship in January. "Man, I think if people are happy then that's what's most important, period," Amber said on the Allegedly With Theo Von & Matthew Cole Weiss podcast. "They're working out. Chyna's cooking healthy meals for him. It's a really, really good vibe."