How is it that Aug. 21 has not yet been declared Dirty Dancing day? On this date 35 years ago, the little rom-com-musical directed by Emile Ardolino hit theaters and soon became a global sensation. The story centered on young, idealistic Baby Houseman (Jennifer Grey) and her summer romance with sexy dance instructor Johnny Castle (Patrick Swayze), and it brought us a host of memorable dance moments, from the sexy "Love Is Strange" duet to The Lift™.

Today, however, we're here to celebrate a different Dirty Dancing moment — perhaps the most iconic number in the entire film. Today we honor Baby's vain and fabulous older sister, Lisa Houseman (Jane Brucker), and her mesmerizingly tone-deaf performance of a quirky little song called "Hula Hana." Though Lisa's song and (very awkward) dance was initially only supposed to play out in the background as Baby watches Johnny back out of a gigolo date with Vivian Pressman (Miranda Garrison), Brucker's performance was so captivatingly kooky that Ardolino ended up giving it prominent placement in the scene.

The "Hula Hana" remains a fan-favorite moment to this day, but it almost didn't happen. As Brucker tells EW, Lisa's talent show rehearsal was going to be cut from the movie entirely until she and choreographer Kenny Ortega drummed up the little ditty about a spoiled island queen who wants "a pineapple that doesn't sting, a bird that swims, a fish that sings." Read on for Brucker's story about bringing the "Hula Hana" to life — and why it took her nearly two decades to get co-writing credit for the Dirty Dancing earworm.

ENTERTAINMENT WEEKLY: Lisa is a true diva from her first moment on screen, when she's admiring herself in the mirror in the backseat of the Houseman family sedan. How would you describe your approach to the character?

JANE BRUCKER: I wasn't like her at all. I didn't know how to put on mascara until my 20s. My mom was an artist, and she didn't promote all the values that Lisa Houseman has. So to be able to play her was just a real treat for me, to be able to really hop into somebody else and have a teenage-dom that I didn't have when I was a teenager.

[In that first scene] I was thinking, "Oh my God, we're not even driving the car — we're being pulled. Movies are really fun!" [Laughs]

In the original script, what was Lisa supposed to be singing during the talent show rehearsal scene?

They wanted "Some Enchanted Evening," and it was too expensive. They were going to cut it. Either [screenwriter] Eleanor [Bergstein] or Emile said, "Unless you wanna write something?" [Laughs] So I'm like, "Yeah. I write stuff doing improv all the time. I'll write something."

So, you just went ahead and wrote "Hula Hana"?

I wrote it. I wrote the story of the spoiled brat living in the island. I can't remember whose idea it was [to make the song] a hula — probably Kenny's. It was all the rage to do tropical [themes] at that time, you know? After South Pacific, everything was tropical.

So, I wrote the story of the spoiled brat on an island, just during breaks — which there were plenty of for me because I didn't have a huge part. [At some point] Kenny said, "Put 'wacka wacka' in it." I thought you couldn't put "wacka" in the song because it sounded like "whack off." I thought he was nuts. "You can wacka if you wanna?" Really? But then I thought, "Wait a minute, the movie's called Dirty Dancing. Maybe I'm just square." [Laughs]

And you also wrote the music?

Yeah. It's a simple little tune.

Simple, yes — but it's also an earworm. Once you hear it, you can't stop yourself from humming it all day. Please do not sell your songwriting skills short.

I thought it was just the last note that people get stuck in their ear, and it drives them insane. [Laughs]

That's true — Lisa's voice is sort of hypnotically off-key. How did you settle on her singing style?

Well, I thought she might hit [the note] and then she'd lose it because she aspires to more than she can do. So, I wanted to hit it and then fall off — just miss it. Like, she's almost elegant but she is not quite there.

There's a moment where Lisa counts to herself while singing ("…and it's worth it when they watch her shake her grass! Four, five…"). Did you ad-lib that?

Yes, I sure did. I had had a very snooty musician boyfriend in the past and I'd always felt really intimidated by him and his friends when they'd sit around and dissect music. I felt like it was a foreign language. So, I threw in the extra numbers there on purpose. [Laughs]

The dance is perfectly ridiculous. Who choreographed it?

It was really, really quick. It was basically improvised because I was given no time. I wasn't even sure that [Emile] was going to get a single shot of it. It was just going be a background thing, and then I was told to go back to my trailer and if there was time at the end, Emile was going to try to get a single shot of it. It was just gonna be way in the background, so it didn't really have to be a big, choreographed dance. Kenny and I [huddled] in a corner and [came up with it].

I waited in my trailer, and then I got a knock on the door and so we did it in two takes. It just wasn't very complicated. It was pretty improvised with Kenny. He [came up with] more of the elbow stuff, and I didn't understand what he was doing. But now I do, because that's how the men on the islands dance.

And the bow at the end?

That was probably me. I don't take sole credit for any of it, but I think the bow was me.   

What did you think when you first saw Lisa's "Hula Hana" moment on the big screen?

The real charge was later — I think it was like the 10th anniversary of the movie. There was some film festival anniversary screening, and we were all getting together. I walked into a movie theater in L.A., and nobody recognized me. I totally felt anonymous. [At the beginning of the talent show rehearsal scene,] the camera pans over from the piano player. In the screening when the scene started, the audience started cracking up and applauding. I went, "Whoa!" They knew what was coming and they laughed and showed appreciation. Before that moment in the screening, I thought, "Well, I had a nice little part in a movie once, big deal." But when that piano started and everybody started laughing, I was like, "They noticed!"  

It wasn't until many years later that you got credit for co-writing the song. How did that happen?

I did finally. In 2004, somebody at a dinner party happened to mention that they were doing a live stage production of [Dirty Dancing] in Australia. They turned it into a musical. [At the time of filming], I thought, "Well, I don't want to piss off the producers and insist I should get something for writing the song." So, I let it go. And then when the movie got big, I had no recourse because it had been too many years [and the statute of limitations had run out]. But when they did it as a stage production, I was able to get credit [for the song] written for the stage, and therefore retroactively whenever it plays in the film as well. I was able to collect. [Laughs]

When I first heard about the song being used in a stage musical, I got in touch with Kenny Ortega. I was on a cell phone at the farmers market here in L.A. and he's going, "Oh Jane, of course. We'll split it 50-50. Let's do it." But then he goes, "I'll do it if you sing that last note at the end." I was like, "Kenny, I can't. I'm in a parking lot at the farmers market." He said, "No, I'm not gonna do it unless you sing the last note!" So, I bent into my car and sang, "Away, away, awaaaaaaaay." He said, "Thank you very much." And that was that.