Watch I Know This Much Is True online: Start time, HBO release date, cast, trailer

How to watch I Know This Much Is True online
(Image credit: HBO)

We get Mark Ruffalo times two when we watch I Know This Much Is True online on HBO tonight. 

I Know This Much Is True is a six-episode limited series based on the bestselling novel by Wally Lamb, which was selected to be part of the Oprah Winfrey Book Club. The adaptation comes from writer/director Derek Cianfrance, the auteur behind Blue Valentine and The Place Behind the Pines. 

I Know This Much Is True release date, start time

I Know This Much Is True debuts tonight (Sunday, May 10) at 9 p.m. Eastern on HBO.

The story follows identical twin brothers Dominick and Thomas Birdsey and their trials and tribulations. Melissa Leo, Rosie O’Donnell, Archie Panjabi and Imogen Poots are also in the cast of I Know This Much Is True.

Ruffalo has spent recent years as Bruce Banner / The Hulk in the Avengers movies, but he's also an Oscar-nominated actor from Spotlight, Foxcatcher and The Kids Are All Right. He also won a SAG for his role as a gay writer and activist in HBO's Normal Heart television movie. 

He is serving as an executive producer on I Know This Much Is True, which HBO describes as a "family saga" and an "epic story of betrayal, sacrifice and forgiveness." The unflinching, grim narrative delves into Thomas' paranoid schizophrenia and Dominick's struggles to help his brother while dealing with his own failed marriage and the death of his infant child. 

Here's everything you need to watch I Know This Much Is True online:

How to watch I Know This Much Is True premiere online anywhere on Earth with a VPN 

Just because you're in a part of the world that doesn't get HBO doesn't mean you have to miss out on the premiere episode of I Know This Much Is True. With the right VPN, you can stream the show from wherever you go.

Our testing shows that the best VPN service is is ExpressVPN. It meets the VPN needs of the vast majority of users, offering outstanding compatibility with most devices and impressive connection speeds. Signing up for longer periods of six months or a year reduces the cost even more.


Our favorite VPN service, ExpressVPN, will shine for the Westworld S3 premiere thanks to its safety, speed and simplicity-to-use. It's also compatible with loads of devices - from iOS and Android to Roku, Apple TV and PlayStations. You'll even get an extra 3 months free if you sign up for a year, or there's a 30-day money-back guarantee if you just want to give it a try.

Where to watch I Know This Much Is True episode 1 online in the US 

For US viewers, I Know This Much Is True episode 1 premieres tonight (Sunday, May 10) at 9 p.m. Eastern on HBO, if they subscribe to the premium cable network. They can watch through their cable package or stream it live on HBO Go

If you don't have cable, you can sign up for HBO Now, which is $14.99 per month. 

HBO is also available as an add-on to most popular live TV streaming services, such as Sling TV, Hulu with Live TV and YouTube TV.  HBO is even available a la carte on Apple TV Channels.


The free 7-day HBO Now trial will last long enough for you to test the waters. You can catch up on Westworld season 3, check out the new comedy Run from Fleabag creator Phoebe Waller-Bridge and, of course, binge all of Game of Thrones. 

Where to watch I Know This Much Is True in the UK

Good news, Brits! You can watch I Know This Much Is True the day after it airs in the US, starting Monday, May 11 at 9 p.m. BST on Sky Atlantic & NOW TV.

Where to watch I Know This Much Is True in Canada

Even better news for Canadians: I Know This Much Is True will air same time and date as it does in the US on Crave. 

I Know This Much Is True trailer 

Yes, you are seeing double ... double the Ruffalo: 

I Know This Much Is True cast 

As we've mentioned a few times, Mark Ruffalo leads HBO's adaptation as twin brothers Dominick and Thomas Birdsey. He's joined by some very talented actors. Here's who else is in the cast of I Know This Much Is True:

  • Melissa Leo as Ma
  • Rosie O'Donnell as Lisa Sheffer
  • Archie Panjabi as Dr. Patel
  • Juliette Lewis as Nedra Frank
  • Kathryn Hahn as Dessa Constantine
  • Imogen Poots as Joy Hanks
  • Aisling Franciosi as Young Dessa Constantine
  • Simone Coppo as Vincenzo Tempesta
  • Marcello Fonte as Domenico Onofrio Tempesta
  • Bethany Kay as Miss Haas
  • Philip Ettinger as Young Dominick and Thomas Birdsey
  • Brian Goodman as Al
  • Bruce Greenwood as Dr. Hume
  • Guillermo Diaz as Sergeant Mercado
  • John Procaccino as Ray Birdsey
  • Michael Greyeyes as Ralph Drinkwater
  • Rob Huebel as Leo

I Know This Much Is True reviews

The reviews for I Know This Much Is True all laud how well the series is made, from Cianfrance's writing and directing to the performances, particularly by Ruffalo. However, the critics also note how dark and depressing the story is. Here's a roundup of reviews.

AV Club: "I Know This Much Is True may not be an enjoyable watch, but it still manages to be an arresting one, thanks to the stellar performances of an impeccable cast."

Rolling Stone: It's "so relentlessly, almost proudly, miserable at every possible turn that, after a while, I began looking at the project as an unexpected form of public service. Hard as it was to get through each hour — let alone the 79-minute finale — I would depart its world each time and feel a little bit better about the current state of my own life. And that’s in the middle of a pandemic quarantine!"

The Hollywood Reporter: "... if the performances in I Know This Much Is True weren't as terrific as they are, the catharsis probably wouldn't justify the exhausting duration."

The New York Times: "And while I Know This Much Is True pulls you along on the strengths of its soap opera mechanics, its smoothly downbeat vibe and Ruffalo’s performance, it promises more than it delivers — eventually the story collapses in on itself, settling for the sentimental formulas it’s been pretending it was above."

Kelly Woo
Streaming Editor

Kelly is the streaming channel editor for Tom’s Guide, so basically, she watches TV for a living. Previously, she was a freelance entertainment writer for Yahoo, Vulture, TV Guide and other outlets. When she’s not watching TV and movies for work, she’s watching them for fun, seeing live music, writing songs, knitting and gardening.