Beyonce's Daughter Blue Ivy Makes Unforgettable Cameo In HBO Doc

Fans will see 'me being introduced to who I am from my daughter,' Beyoncé had teased to MTV News before Saturday's premiere.

To get how fiercely protective Beyoncé is of her privacy, remember that the first-ever glimpse of her 2008 wedding to Jay-Z came more than three years later in the form of a concert DVD and clocked in at just under two seconds. No Mr. Carter, no I Do's, just a beaming Bey in white. This makes the closing scenes in her new HBO documentary nothing short of a revelation.

After a red-carpet premiere in New York City last week, "Life Is but a Dream" debuted Saturday night, and if you weren't at one of many viewing parties across the country, then we should warn you that there are definitely spoilers ahead.

"This film is about a woman and all of the challenges that we all go through," Beyoncé told MTV News when we spoke to her at the Ziegfeld Theatre screening.

For superstar Bey, those challenges include adapting to a brave new world ruled by social media, nurturing her marriage to a man who's arguably the most famous rapper alive, and strategizing how to hide her first pregnancy before finally announcing it at the 2011 MTV VMAs. Really, though, all of those onscreen story lines touch on the singer's battle balancing her private and public lives. The birth of her daughter — whose arrival was covered in messianic fashion — no doubt intensified that internal struggle. But by the end of the doc, it's clear the new mommy has decided to make some concessions.

As the pop diva's relatives gather around a large, well-lit dining table, poring over family photos, the camera closes in on Beyoncé gently pacing back and forth, holding her daughter. Yes, after a year of carefully obscured Tumblr photos and grainy paparazzi pics, mother and gurgling child are finally in focus. And there are no beaded Elie Saab couture gowns here, no wind machines. It's just Bey, hair braided and casual in a jumper, giving the adorable Blue a bottle and, as she put it last Tuesday, "connecting all of the dots" in her outsize life.

In the theater that night, even the seen-it-all journalists tapping out notes on their iPhones let out a collective gasp during those intensely personal scenes. (Only Oprah Winfrey's surprise appearance at the event elicited a reaction anywhere close.) Beyoncé promised that fans watching the doc would see her "eventually being introduced to who I am from my daughter," and we think she delivered.

What did you think of the documentary "Beyoncé: Life Is but a Dream"? Sound off in the comments!