Longtime pals Jon Stewart, host of 'The Daily Show,' and Brian Williams, NBC's 'Nightly News' and 'Rock Center' anchor, are about to be in the midst of a friendly feud -- at least if Stewart has anything to say about it.

Last night (Jan. 17), Lena Dunham -- actress, director, writer, producer and Howard Stern apology acceptor -- went on Stewart's show and they briefly discussed Brian's daughter Allison, who's one of the stars of Dunham's HBO series, 'Girls.'

"Is there anything that you could do to make [Brian] more uncomfortable?" Jon requested of Dunham, adding, "I say this to you, as a personal favor to me."

Stewart was of course referring to the fact that 'Girls' is chock-full of sex scenes, some of which feature Allison. And seeing your daughter get bizzy on TV has got to be right up there on a father's worst nightmares.

Dunham replied, "As a fan of his, I've often talked about how I wanted to have, like, a Brian Williams cam where there's a camera on him watching the sex scenes and we get to see it play in real time. That's a dream of mine."

"I say this to you not as a sage. Not as a wise person. Follow your dreams," Stewart quipped. "I would very much like in on that."

Lena concluded the interview by promising to brainstorm “some new demented ideas” and “sexual positions” if the show receives a third season. Which, as a Golden Globe-winning show, it most likely will.

In other words, HBO might soon lose a subscriber: Brian Williams.