Someone told me that it is Mama Mia 2.. Is this correct or is it the original?

It is the original. The source is wrong.

I'm going to see the original Mamma Mia at the North Shore Music Theatre opening night Wednesday. After work I hope to go to the movie theaters to see Mamma Mia 2

mamma mia 2 is in theaters now. The production at NS MT is the original Mamma Mia.

Believe it is the original. 2 is just released as a film.

Have no idea. Not my kind of show. Sorry