The 36-year-old actress, however, said she found it incredibly "rewarding" in the end, reported People magazine.
"I was actually on both sides [of the camera]. It was an undertaking, but the movie was produced by Jane Rosenthal and you couldn't ask for a better producer, so I felt very taken care of.
"It was very challenging! But very, very rewarding. Hopefully you just get better every time you do it. That's what I'm hoping for," Holmes said.