Bradley Walsh's Graham has become the best part of Doctor Who season 11. This season has brought many changes to the show; new showrunner, new writers, a new Doctor, and new companions (or friends as the Doctor now calls them). Almost all of these changes and new additions have been positive; Jodie Whittaker has made a strong first impression as the first female Doctor, and looks set to become a fan favorite for many. Her friends too, have received a positive reception from the fandom, and none more so than Graham.

When the casting of the new companions was first announced, it raised some eyebrows. Three companions instead of one was shocking to begin with, but at least both Yaz (Mandip Gill) and Ryan (Tosin Cole) are young, dynamic and diverse. Walsh's Graham is.., not. Putting a white, middle-aged man into the TARDIS could have been a move that backfired, but it's actually proved to be a stroke of genius, and it's testament to Walsh's acting abilities that it's worked so well.

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Walsh was already a household name in the UK when he was cast in Doctor Who, though he was more known as a presenter, having hosted many TV game shows including the long-running quiz show, The Chase. He had starred as an actor though, most notably in Law & Order U.K. and Coronation Street, but no one seemed to be expecting that he would be capable of delivering such a subtle, nuanced performance as he does in Doctor Who.

Nearing the end of Doctor Who season 11, it's now clear that Graham has had the best arc of all the new characters, having been on an emotional roller coaster right from episode 1. The death of his wife, Grace, left Graham grieving, but also trying to care for his step-grandson, Ryan, who was emotionally closed-off from him. This grief has made itself known throughout the season, especially in episode 9, "It Takes You Away." There, Graham was reunited with Grace in a mirror world, where a force called the Solitract takes on the form of those we love the most.

Graham ultimately knew the Grace standing before him wasn't real, but that didn't make his reunion and subsequent departure any less heartbreaking to watch. Walsh played these scenes brilliantly, downplaying the magnitude of the situation just enough to present a man who was one fragile step away from losing it completely. The subsequent scene with Ryan, who called Graham granddad for the first time, highlighted the chemistry between this new Doctor Who cast, who gel together seamlessly.

But Walsh doesn't need to be the center of attention to deliver a great performance, as seen powerfully in Rosa. Graham served very much as the protector in this episode, standing up for Ryan and making it known he was his grandson, regardless of color, and sticking close by the Doctor to make sure she was safe. As he realized what was about to unfold on the bus, his heartbreaking "No, no, I don't want to be a part of this," was the most resonant, and the sheer desperation on his face as the Doctor told him he must stay there was deeply upsetting.

Graham isn't all about heartache, though. Walsh is renowned for his comedic presenting style, and he's transferred this skill seamlessly to his role in Doctor Who season 11. His relationship with the Doctor is multi-faceted; both respect and like each other a great deal (his nickname for her, "Doc", is a masterstroke), yet he becomes exasperated with her thirst for adventure, much like a father would with an over-exuberant teenager. Equally, she can assume a teacher role, while he is the inquisitive, talkative child who can get on your last nerve. The Doctor can't get mad at him, though; Graham is too endearing for that. Instead, she simply states her case, shuts him up firmly, and carries on with what she was doing in the first place, while Graham follows behind, muttering all the while.

Graham is most of us, regardless of our own age, gender or race. Every time the TARDIS arrives on a new planet, or in a new era, he is the one with the questions, the reservations, and the astonishment as the Doctor heads off eagerly into the unknown. Walsh's line delivery is always on point, never overshadowing the Doctor, Yaz or Ryan, but still standing out. A joy to watch each week, fans are already looking forward to seeing what Walsh will deliver in Doctor Who season 12.

Next: Why Doctor Who Has Completely Divided Fans This Season

Doctor Who continues on Sunday, December 9th on BBC America.