The couple was overheard talking about the happy news at a Gucci party hosted by music producer Mark Ronson in London on Wednesday night (21Apr10).
A source says, "Bonnie was even showing off her glittering engagement ring."
Wright recently went public with the romance six months after she started dating The Twilight Saga: New Moon star.
She cooed, "We met at a party and we just really clicked straight away. He's a great guy, and we just enjoy spending time together... He's really lovely. Everything is going great."
The two stars met on the set of the upcoming Harry Potter and The Deathly Hallows: Part 1.