Frank Grillo Stunned Costar John Cena Got Hair Transplant, Had No Idea! | TMZ TV

Frank Grillo Stunned Costar John Cena Got Hair Transplant, Had No Idea! | TMZ TV

We chopped it up with Rick Flag Sr. out at LAX ... and while we chatted a bit about the new season of the hit Max show dropping later this year (skip the first 30 seconds of the clip if you haven't watched S1 yet), the topic of the WWE Superstar's recent life-changing decision made Grillo stop in his tracks.