'Knightfall' Sneak Peek: De Nogaret Tries to Expose Landry's Big Secret -- But Does He Have Proof? (Exclusive)

De Nogaret's attempt to get back into the king's good graces might just work.

The secret's out!

Only ET has a sneak peek at Wednesday's episode of Knightfall, in which De Nogaret (Julian Ovenden) tries to get back into King Philip's (Ed Stoppard) good graces -- by revealing Landry (Tom Cullen) and Queen Joan's (Olivia Ross) affair. 

"Your grace, think for a moment. She would not share your bed for two years," De Nogaret tells a shocked King Philip, who insists his and Joan's recent reconciliation makes his claims untrue. 

"I would guess not until after she discovered she was with child, so that she could hide her transgression from you," De Nogaret continues. "I have a man inside the temple. Landry confessed to him." 

"He mentioned Landry by name?" Philip asks, growing enraged by his wife's infidelity. "This is all hearsay, slander, lies!"

"Your grace, if she did not come to your bed for two years, whose bed was she going to?" De Nogaret replies. 

See what happens next in the video player above. 

Knightfall airs Wednesdays at 10 p.m. ET/PT on History. 

ET recently spoke with Ovenden, who teased that his character's discoveries would soon connect with Landry's search for the Holy Grail. 

"They do intertwine, and intertwine in a way that you're not going to expect. There's great twists," he promised. "There's a couple of new characters that come in towards the end of the season that change things somewhat. I think we're really proud of the last episodes, because the intensity racks up, and everything's on the line."

See more on Knightfall in the video below.