What Is William's Secret On 'This Is Us? He's Hiding Something From Randall

William has been full of surprises since his introduction on This Is Us, from being a decent man to having terminal stomach cancer, to having a preconceived relationship with Rebecca, Randall's adoptive mother. But now, according to the promo for Episode 7 "The Best Washing Machine in the Whole World," he's hiding something else. So what is William's secret on This Is Us? In the clip, William is seen telling Randall's wife, Beth, something that no one else seems to know about, to which she replies that she has to tell Randall. But at this point, what could William be hiding exactly?

This Is Us has always been a show that prides itself on twists, turns, and shocking surprises to leave viewers wanting more, but it's hard to figure out what William's next big surprise could be. In the flash forward on another episode, it was all but confirmed that William is going to die at some point, so the chance that his health has gotten better is likely not the big secret he reveals to Beth. Still, if it doesn't have anything to do with his health, then what could it be?

William has proven himself to be a decent man now, who just wants to continue building a relationships with his new family, so figuring out what his secret is might be the thing to put all of that in jeopardy.

So what is William keeping from everyone on This Is Us? There may not be many juicy secrets left to tell regarding William, but there are a few good possibilities that would make for excellent drama — and tears all around.

He Wasn't Truthful About His Health

As far as viewers know, William has stomach cancer that hasn’t given him much time left to live, so he’s been living out his final days with Randall and his newfound grandchildren. But what if there’s something else that he isn’t telling Randall? Like, what if he found out something else about his health, like that there’s hope, despite what the doctor most recently told them? It’s a long shot, sure, but you can never be too thorough when all you want to do is hope for a happy ending.

It's About Randall's Birth Mother

The only thing that’s known about his birth mother is that she and William had him out of love but that she was gone shortly after his birth. I can’t remember if she died or just left, but either way, William was left with a baby he couldn’t take care of. So it’s entirely possible that, with all of the mystery surrounding Randall’s birth mother, there is something William is holding back about her that could be pivotal to the show.

The Secret Is About His Communication With Rebecca

Earlier this season, Rebecca met with William in private to ask him about his re-connection with Randall and in the same episode, viewers were given a flashback which showed her meeting with him shortly after she and Jack adopted Randall as a baby. But Randall knows none of this, so William’s secret on could be that he let the truth about that slip out when talking to Beth.

William’s secret on This Is Us is obviously going to have a huge impact on Randall, as the promo seems to suggest by Beth’s reaction, but the truth behind it could be any of these options. But is it too much to ask that William isn’t blamed for any of it at this point? He’s kind of becoming a favorite. He is the wise old owl, after all, and the series wouldn't be the same without him.