The 30-year-old rapper posted a tribute to Fox on Sunday, February 14, where he showed fans a necklace with a drop of what appears to be blood inside alongside a collection of their sweetest selfies.
The first pic was a selfie Fox took in the mirror where she draped an arm around her man; the cute pic was followed by the unusual bloody pendant. The "Bloody Valentine" singer also shared a black-and-white photo of the brunette beauty hugging his waist and a clip of the pair goofing off with an inflatable pool flamingo.
"I wear your blood around my neck 🔪🩸," he captioned the series of snaps.
"THE BEST BLOODY DUO," one fan joked in the comments.
"the blood on the neck is rlly romantic wtf," another noted.
"Kinda weird bro," a third fan admitted.
Fox shared her own Valentine’s tribute to her partner but didn’t mention if she wears a blood necklace, too.
In the first snap, she posed in front of her beau as he took a photo in the mirror, which was followed by a clip of her playfully standing on his feet from behind. The couple struck a pose with their tongues out in the third pic which was followed by a pic of Fox leaning in for the kiss while Kelly licked her mouth.
"There goes my heart / manifest outside of my body / draped in the towering silhouette of a most unusually handsome boy," Fox captioned the series of snaps.
"Magical and haunted / kinetic and tortured / ethereal and dangerous / cosmic / lawless / eternal /creative genius / the journey will likely be perilous /but there is no destination without him," she added.
"Happy valentine’s day rehab barbie."
Kelly, who was born Colson Baker, has been linked to Fox since last summer when they met on the set of Midnight in the Switchgrass following Fox’s split from estranged husband Brian Austin Green.
"MGK is head over heels in love with Megan, and he feels like he's only sharing half of her life. He wants to spend time with the boys [Fox's children, Bodhi Ransom, Journey River and Noah Shannon] and have them join him and Megan to go to the park, the zoo, and do family things," a source previously told OK!.
As OK! previously reported, Fox wants to finalize her divorce as quickly as possible.
The Jennifer’s Body actress is "very serious with MGK and sees him as her soulmate and life partner," a source told E!. However, Green is said to be happy for his ex and is not bothered by the couple getting serious.