Gad made the remarks in a HuffPost Live interview. He said, “I would actually love to [be involved]. I would read the phonebook if Trey [Parker] and Matt [Stone] asked me to do the film. I feel an enormous sense of graciousness that they came to me with that project and allowed me to make my mark as Elder Cunningham, and I would jump at the opportunity to do the film. I fear that I may be a little old, but hopefully I can be involved in some capacity.”
In the interview Gad also said the state of of Broadway is "amazing" and gave props to Hamilton, saying, "It's the greatest piece of musical theatre I have ever seen."
Here is the interview: