At the norwegian court the Ladys in waiting title was removed in september 2001. Only Princess Astrid, the Kings sister still has one. That does not mean that the royals go out alone for engagements, but it is usually called the more gender neutral "protocoll secretarys" the King and CP Haakon has Aide de Camps from the military with them, they wear uniforms
I dont think Mette-Marits assistant would be very happy about beeing called a lady in waiting, seeing that he is a man
His name is Anders Flågen and he used to be a Haakon Aide de Camp from the military before he was hired at the Crown Princely Household. Here he is with Mette-Marit at some occations, I have put a red arrown on him as he keeps very much in the background and not as prominent as Marys lady in waiting but he does more or less the same job. Now it is not always Flågen that goes with her, sometimes there is someone else but he is most commonly seen with her, forinstance on her trip to Malawi (first pic). Cabinett secretary Berit Tversland who is one of the highest ranking women at the court very often accompany the Queen
For very formal occations like the Japanes statevisit Mette-Marit was accompanied by a lady from the court (green arrow) but I dont know her name.
(Pictures from colourpress, aftenposten and ob.no)
Here is Princess Astrids Lady in Waiting behind Princess Märtha Louise, you can see she wears a red ribbon on he jacket with Astrids monogram, the protocol secretarys or other court memebers dont wear theese as far as I know, I dont know why Astrid kept her lady in waiting, maybe she insisted
When Princess Märtha Louise does royal duties she is accompanied by her secretary Mari Sørlie