Comedian Pete Davidson began dating the No Tears Left To Cry singer in May and earlier this month it was reported the pair, both 24, were engaged.
There has been no official confirmation but Grande has been pictured with a ring on her finger.
Now, Davidson has fuelled the rumours and posted a black-and-white snap on Instagram of the couple’s hands, showing off the diamond.
He captioned the image: “u know what you’d dream it be like ? it’s better than that.”
Grande replied to the post, saying, “So much better” along with a heart emoji.
The post has been liked more than 300,000 times.
Since news of their relationship broke, Grande and Davidson have documented their romance on social media, sharing several candid posts.
One showed Davidson cuddling her from behind and planting a kiss on her cheek.
Grande captioned the image: “i thought u into my life, woah ! look at my mind.”
They originally announced they were dating when they appeared in a picture on Davidson’s timeline dressed in Harry Potter costumes, as he joked: “the chamber of secrets has been opened …”
Grande, who in May marked the one-year anniversary of the terror attack at her concert in Manchester, only recently ended her previous relationship with rapper Mac Miller.
She described her relationship with Miller as “toxic” and said she was “not a babysitter or a mother” in response to a comment from a fan that their split was “heartbreaking”, after he was reportedly arrested on suspicion of drink-driving.