The 74-year-old from Cork picked up some Christmas decorations from Dunnes Stores two years but only chose to put them on her tree this year.
Her hilarious mix-up was soon discovered by her granddaughter, Alex Bermingham, who took to Twitter to share the brilliant story with her followers.
Alex's amusing story comes after a woman moved the internet to tears earlier this month with an emotional story about the nicest Christmas gift she ever received.
'My 74-year-old grandmother bought Christmas baubles in [Irish retail chain] Dunnes Stores, which I have just realized upon decorating her tree that unbeknownst to her upon purchase, they are in fact, lavender glitter G-strings, ' she wrote.
"She never realised until they were pointed out to her".
"Wishing everyone a kinky Christmas this holiday season".
Speaking to Metro.co.uk, Alex revealed that her grandma had bought the decorations years ago, but had only brought them out now. "My reaction consisted of pure shock and laughter at the situation!"
"They have to be!", joked Alex.
And Alex's hilarious tweet has already racked up nearly 6,000 retweets and has been liked over 22,000 times.
Alex revealed her reply: "She relied with "Jesus Al yer man in the shop must have thought I was very kinky sure I bought six of them". One Twitter user said: "Oh my god, that's hilarious ".