Labour under the delusion, illusion, misapprehension, etc. verb phrase
To wrongly think or believe something to be true
At the competition, he was still labouring under the illusion that his picture was the unique one.
Jason laboured under the misapprehension that every member of the team had respect for him.
Marry always labours under the delusion that one day she will become a superstar in the entertainment industry.
The verb "labour" should be conjugated according to its tense.
A humorous way of saying that what one has said is just what they acknowledge and may not be entirely accurate
Mike: Have you returned from your vacation on the beach? Your skin seems to get tanned.
Jenny: My skin is always dark. That's my story and I'm sticking to it!