The 19-year-old singer and actress posted a photo of a sparking ring featuring the initial J to her Twitter on Sunday.
It appeared to be festooned with tiny diamonds and fitted snugly on the middle finger of the Disney's star's right hand, which was being held by a mystery set of (rather larger) digits.
She wrote enigmatically next to it: 'I'm finally home '
The brunette had arrived back from her latest show in Montevideo, Uruguay, and straight back into the arms of her 17-year-old superstar boyfriend.
It marked the end of a world tour that began in July.
As it drew to a close, Gomez announced she was taking a break from music to focus on her acting career.
I don't think it's real. Justin doesn't turn 18 for another 2 weeks so if Selena got engaged now she'd probably get arrested or something. But of course, they're a celebrity couple so anything can go they're way.
But I don't think Selena is ready to get married anyway. She's only 19
Queens: Miley Cyrus, Avril Lavigne, Rihanna, Carly Rae Jepsen, Selena Gomez, Ashley Tisdale, Katy Perry, Lady GaGa, Ke$ha
Princesses: Britney Spears, Demi Lovato, Fergie, Ellie Goulding, Cher Lloyd, Jessie J, Taylor Swift, Hilary Duff, Ashlee Simpson
MICHAEL JACKSON The King of Pop
Over 750 Million Records Sold | 17 #1 Singles | 736 + Presidential Awards Won | CAREER Lasting 4 Decades | Most Successful Artist Ever | Influenced Millions |31 GUINNESS World Records| Greatest Performer Ever | Ultimate Icon/Legend | Best Selling Album Ever |
~Humanitarian :Donated over $300 million to charities
~Most Iconic Dance Ever : Moonwalk