She opened up about her gaffe to her fans on Instagram, sharing a picture showing her sat on the sofa in her PJs watching the show with the words “When you feel like you've forgotten something?" and a laughing emoji.
A picture of her phone calendar showed she had marked the date - 9 September - of the event.
“Another thing I forgot to do tonight. Go to the NTAs. Whoops!" she said in a video clip also shared to the site.
Earlier, Solomon had told fans that her day had been a bit of a “write off”, saying she’d had plans to do some painting but that she had ended up running out of time before she had to collect her sons from school.
She also had to clear up the kitchen and said she fancied a takeaway that night so she didn’t have to get things messy all over again.
And it seems that because of her busy day Solomon completely forgot about the awards ceremony, as an hour later she shared the clip of her sat down watching all the action on TV.
The TV star announced in June that she and her fiancé Joe Swash were expecting their second child together after suffering miscarriages, and later confirmed they were having a baby girl.
The couple already share two-year-old son Rex and Solomon is mum to sons Zachary, 13, and Leighton, nine, from previous relationships.
Swash has son Harry from a former relationship.
Watch: Stacey Solomon is expecting a baby girl