After months of rampant rumors and hype, Apple debuted its latest smartphone Wednesday in front of a packed house at the Yerba Buena Center for the Arts, claiming it is the world's thinnest.

The iPhone 5 features a larger screen and weighs 112 grams, or about 4 ounces, which is 20% lighter than the iPhone 4S. It is also 18% thinner, Apple's marketing chief Phil Schiller said. It has an improved A6 processor that is twice as fast as its predecessor, high-speed 4G LTE connectivity and a widescreen aspect ratio.

Apple has also improved the device's battery life and updated both of its cameras, giving its front camera 720p HD video. The company also announced a smaller dock connector for the device and a new cable charger named Lightning that is 80% smaller than its predecessor.

Siri got a makeover as well, and can now tell users the scores of sports games and post status updates to Facebook.

The iPhone 5's dock connector has also been made smaller.

The device will be available in black and white. It will be available for $199, $299 and $399 for 16GB, 32GB and 64GB models, respectively. Pre-orders begin Friday and the iPhone 5 will launch Sept. 21.

The company said iOS 6 will arrive as an update for many of its iOS devices Sept. 19.

The invitation-only Apple event, which began at 10 a.m. Pacific time, is still ongoing. Cook is expected to announce upgrades to other products, including the iPod, soon, so check back for updates.

For live tweets from the event, click here.

The launch of a new iPhone will mean huge sales for the Cupertino, Calif., tech giant.

Since the original iPhone debuted in 2007, Apple has sold more than 244 million units and has been credited with upending the smartphone industry.

Sales of iPhones and related products and services accounted for 46% of Apple's revenue in the most recent quarter and 58% in the previous quarter. In its last fiscal year, the company reported revenue of $47.1 billion from sales of iPhones and related product and services, an 87% increase over the year before.

Analysts estimate the iPhone has a gross margin of about 50%, making it an extremely profitable device for the world's most valuable company. Nearly two-thirds of Apple's profits come from the iPhone.

With sales of Apple's iPhone 4S and earlier models dropping off in recent months, analysts believe there is huge pent-up demand for the iPhone 5. Many have predicted that Apple could sell up to 10 million iPhones in the first 10 days, and up to 50 million in the holiday quarter.

Also at the event, Cook introduced the audience to the upgraded versions of the iPod Touch and iPod Nano.

The iPod Nano got bigger and slimmer; its display now measures 2.5 inches diagonally, while its body is 5.4mm thick and weighs 1.1 ounces (31 grams). The new line of Nanos comes in 7 vibrant colors, accepts multitouch input, sports an FM tuner and even lets users watch video and view photos, per Engadget's live blog. Battery life will last for up to 30 hours of music playback. There's also Bluetooth and a built-in pedometer. Like the iPhone 5, the Nano will accept the new Lightning connector.

The Fifth-generation iPod Measuring 6.1mm thin and weighing 3.1 ounces (88 grams), it's the "thinnest iPod touch" yet. It boasts a display that's the same 4-inch size as the iPhone 5, as well as a 5-megapixel iSight camera. Apple equipped the new iPods with A5 chips for faster processing and better graphics rendering, and the device now comes with Siri, Apple's personal digital assistant. The battery life has been boosted to allow for 40 hours of music-listening,

The New York Times reports that the 32-gigabyte model of the new iPod Touch will start at $299 while the iPod Shuffle (2-gigabyte) will cost $49 and the iPod Nano (16-gigabyte) will sell for $149. As expected, Apple has dropped the price of the older versions of it 16- and 32-gigabyte iPod Touch models, which will sell for $199 and $249, respectively.