If the art world and the hip-hop world have one thing in common, it's a hearty appetite for controversy. (And before members of both camps start flaming me, yes, I realize they have more than just that in common.) So it was probably inevitable that Jay Z's decision to stage a "performance piece" at the Pace Gallery over the course of six hours would stir passions. To some in the art world, ever suspicious of celebrity incursions, it was a debasement of the form. To some in the hip-hop world, ever suspicious of crossover betrayals, it was a flagrant display of elitism.

But what was Jay Z himself trying to achieve? According to Mark Romanek, who conceptualized the event and directed the resulting half-hour documentary (set to air on HBO this Friday at 11 pm), the inspiration was simple. Romanek had seen the 2012 film "Marina Abramovic: The Artist Is Present," which documented the Serbian-born artist's marathon series of one-on-one interactions with visitors at the Museum of Modern Art in New York, and become fascinated by the intimacy she achieved. "What I pitched to Jay was: 'You regularly perform to 60 or 80,000 people at a time. What if you performed for one person at a time? What if it was like Marina's piece?"" Romanek says.

That helps explain why Romanek insists on calling the "Picasso Baby" session a piece of performance art, rather than a music video. And it helps explain why Jay Z rapped the lyrics live instead of lip syncing -- despite what you may have read in Gawker or The New Yorker. "They're both dead wrong," Romanek says. "At no point during the day did he lip sync. He did live vocals for six hours. The finished piece was always intended to be live vocals. I mean, that was the whole point of it. Otherwise, it would turn into a music video."

Romanek has directed some of the most memorable music videos of the past 20 years, including Johnny Cash's "Hurt," Fiona Apple's "Criminal" and Jay Z's "99 Problems," but he's mostly focused on features these days. His 2002 film "One Hour Photo," with Robin Williams in the lead, grossed $31 million domestically, and in 2010 he followed it up with "Never Let Me Go," starring Carey Mulligan and Andrew Garfield. So when Jay Z called and proposed a collaboration, Romanek had to ask himself if he wanted to do another music video. "And the answer was no," he says. "But do I want to work with Jay Z on this amazing album? The answer was absolutely, so how do we invent a new thing that we would both be excited by?"

I chanced into an invitation to the "Picasso Baby" shoot (event? happening? I don't know what to call it anymore), and thought it was pretty cool. Earlier this week, I asked Romanek how it all went down. Here are some highlights from our conversation.