is there a phrase like this

I don’t know if there is an equivalent of the phrase used in Hungarian, which can be translated as “coming/getting into the picture,” and which approx. means “getting a role.” For e.g. somebody is describing a plan in which several people have different tasks. One of them is curiously waiting to hear what task he’ll be charged with. Getting on that point the speaker tells him “that is where you come into the picture.” It means that he’ll be a key-person on that point in the course of the planned thing. Of course, I know that I could simply say “that is where (i.e. when) you’ll have a role.” I just would like to know if there is also an English phrase sounding like the mentioned one.
It is also used in the following way: when attention is directed to somebody. For e.g. somebody becomes a possible picked person for a job. He/she “gets into the picture.” The same is said (among innumerable cases) also during the investigation of a crime, if somebody gets thought to be one of the potential perpetrators. Or appears as a wittness – it is the same. The point is that he/she suddenly gets a role.