Considering breakfast TV stars are the closest thing we have to legitimate royalty in the Antipodes (especially when the likes of Cate Blanchett, Nicole Kidman and Hugh Jackman are out of town), speculation is mounting that Today's Karl Stefanovic is engaged to his shoe designer girlfriend Jasmine Yarbrough.

The clues, in the form of a diamond ring with more carats than Tasmania has hectares, started dropping on social media last week when Stefanovic marked his partner's 30-something birthday.

The Gold Logie winner posted a photo of Yarbrough embracing two small children with the caption "Happy birthday beauty".

Look closer and the hint of diamond can be seen on the fourth finger of her left hand; a glass of celebratory champagne in the other.

While some were quick to congratulate the pair, it's important to note that none of the couple's inner sanctum called out the rock.

The likes of Stefanovic's manager Sharon Finnigan, former co-host Ben Fordham and Belinda Russell, wife of Today boss and director of morning television for the Nine Network Mark Calvert, commented on the photo with birthday wishes only.

Like any good rom com, the plot thickened over the weekend with the birthday girl herself posting an image on her now public Instagram account, from a "ladies lunch" at Sydney's up market Otto restaurant feat. Stefanovic and the ring.

A guest also published a group shot where the piece of impressive jewellery also appeared.

However no one is speaking publicly about the ring which, within the space of a week, has seen the media morph into Gollum.

The couple and their relationship became front page fodder last year after they met on a boat five months after Stefanovic separated from his wife of 21 years, Cassandra Thorburn.

Speaking of his new flame to Stellar last July he said they were "taking things really, really slowly".

The 'investigation' continues.