Kate Middleton's had an on-again, off-again relationship with her engagement ring for a year. What's the royal secret about ...

Eternity rings are traditionally gifted following a milestone event, like the birth of a child or a wedding anniversary, and are typically covered in diamonds in an infinite loop around the band.

The new sapphire and diamond eternity-style ring first attracted attention when Kate appeared in a video congratulating Team GB athletes on their performance in the Olympics last August.