User blog comment:Anonymous 1029384756/Series Regulars/@comment-74.132.82.188-20180602142740

I also think Jack will remain a regular, if I understand what a regular means. Could someone explain to me the difference between a regular and a recurring guest star? Is the difference the number of episodes they appear in or their importance in the plot? Because there seemed to be a long stretch in Season 13 in which Jack didn´t appear, yet he was a ¨regular.¨