The popstar couple, who have dated on-and-off since February 2010, announced their engagement on New Year's Eve.
The Saturdays singer Wiseman wrote on Twitter yesterday: "Its official Marvin proposed 2me 2day,wanted 2 tell u b4 some1 else did!" and posted a picture of the couple on a Caribbean beach in which her ring can clearly be seen.
The heart-shaped diamond creation has now been identified by The Mail on Sunday as a £45,500 piece from London jewellers Boodles.
Humes had been expected to propose to Wiseman with a Tiffany & Co ring after he booked an appointment with the company in July.
Wiseman was given a promise ring by the JLS star three months before he popped the question.
Watch JLS in the video for 'Take A Chance On Me' below: