Are there any sewers out there who can tell me if an acetate polyester blend fabric is stretchy?

I'm not familiar with fabric types but there is a dress I really want to buy online and its an acetate/polyester blend. The measurements of the dress are about 1"-2" smaller than me and I was just curious if this type of material had any stretch to it so I can fit in it comfortably. I had planned on wearing a shaper with the dress which takes off an inch or so, but i don't want to not be able to breathe all night, so if anyone knows anything about this fabric and how accommodating it is, please let me know, thanks.