The newly betrothed couple stepped out together at the Dolce & Gabbana showroom in Milan on Friday, after announcing earlier this week that Kelly (born Colson Baker) had proposed to the Transformers actress, 35, during a recent trip to Puerto Rico.
Kelly, 31, stood out in a high-neck, hot-pink sweater and checkered gray pants as he held hands with his fiancée, accessorizing with several pieces of jewelry including multiple silver necklaces.
Fox opted for an all-black look that included a minidress with a sweetheart neckline and cutouts throughout, underneath a long-sleeved mesh midi-length frock and black trench coat with a leopard-print fabric inside.
Splash News Online Machine Gun Kelly and Megan Fox
Both Fox and Kelly finished their looks in black shoes — combat boots for the rapper and lace-up heels for the actress — while Fox's stunning two-stone engagement ring could also be seen adorning her hand.
Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human-interest stories.
In a video posted Wednesday, the "Bloody Valentine" musician got down on one knee and popped the question to Fox, who happily accepted. She said the pair also sealed the union by drinking each other's blood.
According to the insider, Fox "loved the proposal" and "thought it was beautiful and perfect." They added, "She is excited to get married."
RELATED VIDEO: Megan Fox and Machine Gun Kelly Are Engaged!
The source also told PEOPLE that Fox is "ready to move on completely" from ex Brian Austin Green, after the two reached a "divorce agreement last fall." (The former couple filed their divorce judgement on Friday, Oct. 15. It will soon be finalized.)
"She has been wanting to get engaged," the insider said of the Till Death actress.
"Megan feels comfortable with everything. She is very happy and feels beyond blessed," the source shared.