The 'Tom Ford' rapper splashed out $2,390 on the jewellery by designer Tacori on the advice of his wife's stylist, Ty Hunter, and was so excited he couldn't wait until tomorrow (14.02.14) to give it to her.
A source told People.com: "[Hunter] got the bracelet and took it with him to give to Jay Z.
"He said Jay was waiting for Valentine's Day to gift her along with a few other presents, but ... Beyonce is always too eager and you can't hold any secret from her, so he decided to give it to her earlier."
The bracelet is made of intertwining silver and gold which "represents two unique individuals" according to the Tacori website, which adds: "The Promise bracelet must be locked and unlocked with a Tacori Key, which symbolises the Promise that is made.
"Once the bracelet is fastened, only the key holder can unlock the promise. The connection chain links both parts of the bracelet and symbolises that the bracelet is always connected."
Jay - who has two-year-old daughter, Blue Ivy, with Beyonce - has previously bought many lavish gifts for his wife, including a platinum covered mobile phone worth $24,000 and her own private island in Florida, worth $20 million.