The singer shared a number of photos of herself and her real-estate agent beau, including one of a huge diamond ring, writing, "Forever n then some," to announce the special news.
The ring features a large oval diamond with a pearl on a platinum band.
The pair was first linked in January this year with their relationship being put on the fast track when they began quarantining together in March.
Hailey Bieber shared her congratulations writing, "YAYYYYYY!!!!! so so happy for you guys!"
"Soooo happy for u guys!!! Love you!!!" Kim Kardashian added.
"Congrats to these two amazing souls," her manager Scooter Braun wrote.
"Ari we love you and could not be happier for you. Dalton you are a lucky man."
Ariana's mum Joan seems to approve of her future son-in-law, writing, "Sooo sooo sooo happy!!!! Love you two!!!!"
Ariana’s fans were seemingly stunned by the announcement.
"I DON'T KNOW HOW TO HANDLE THIS INFORMATION," one wrote, expressing the general mood.
Others called her relationship with Dalton "the cutest thing ever".
A source told People that both families are over the moon about the engagement.
"They couldn't be happier, they're just so excited,” the source said.
“This is a happy time for them, both sets of parents are thrilled."
Ariana has previously shared her love for her new fiancé, calling him her "best friend" and "favourite part of all the days".
Ariana and Dalton first went public in May when he made an appearance in her music video for 'Stuck With U'.
At the time, a source told ET, "Ariana has had some hesitation being so public about her relationship with Dalton as she's seen how that has worn on her past relationships."
Ariana was previously engaged to Pete Davidson in 2018. However, when her ex-boyfriend Mac Miller tragically passed away in September of the same year, the engagement ended.
"I pretty much knew it was over after that," Pete said in an interview with Charlamagne tha God.
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