However, that's exactly what happened thanks to her husband Lee, the Henley Standard reports.
The enterprising spouse got her all dressed up and then drove her to the local golf club, where more than 200 friends and family members were waiting in their costumes to surprise her.
Everyone got involved in the fun, including Hema's 100-year-old grandmother Gertie, who had managed to get dressed up as a kind of Super Gran.
"It was a wonderful surprise. I didn't expect so many people. I am very lucky to have such great friends and family who know how to party," the birthday girl commented.
Wonder Woman is a great superhero costume to choose for a knees up. However, for a little more retro charm, you could opt for an outfit from your childhood like Batfink fancy dress.
Not only will you get plenty of laughs, you'll also have people guessing who is under the bat mask.