Waaiiitt, wait, wait.
The pair were spotted clutching paws in Paris on Sunday evening (above), but they were also seen getting HEAVY into the PDA at Roissy Airport the same day — at one point she even has her head nestled face first into his crotch…
AND Mary Kate was wearing a sparkly ring on her left hand's tell-tale finger!!
Could Mz. Olsen be plunging into the deep sea of marriage with her 43-year-old lover?!
Well, congratz (we guess?!) if these two ARE gettin' hitched! But we somehow think Mary Kate is simply fond of diamonds.
And $55,000 pill backpacks.
[Image via Splash News.]