Taylor Swift, Bruno Mars Join 'Big & Best' Today!

'Big & Best of 2012' live stream, kicking off at noon ET, will also include appearances by Miguel, Norman Reedus and more.

It's 12/12/12, and that means today is the big day!

No, the Mayan Apocalypse isn't happening ... yet. Instead, the "Big & Best of 2012" live stream kicks off at noon ET. It's happening across all digital properties, including MTV.com, VH1.com, CMT.com and ComedyCentral.com, with eight hours of programming and highlights from MTV, VH1, Comedy Central, CMT and MTV2.

"Big & Best" is gonna be as gigantic as this past year was. The special will include appearances from Taylor Swift, who will tease her "I Knew You Were Trouble" video, and "Walking Dead" star Norman Reedus, as well as performances from Grammy nominee Miguel and Unorthodox Jukeboxsinger Bruno Mars, among others.

As if that's not enough, you need to stay tuned all day to see who will win the "Last Fans Standing" competition. Currently, Demi Lovato and her Lovatics are in first place with 328,913 shares, followed closely by Lady Gaga's Little Monsters at #2 with 302,403. The rest of the top seven shakes out like this: Justin Bieber's Beliebers at #3, Selena Gomez and her Selenators at #4, Britney Spears and Team Britney at #5, Beyoncé's BeyHive at #6, and finally One Direction's devotees the Directioners sitting in last place at #7. But all day long, challenges will continue to take place until an artist and his or her fans come out on top.

Tune into the "Big & Best" live stream NOW and see how you can vote in the "Last Fans Standing" competition!

Hosted by MTV News' Sway Calloway, VH1's Carrie Keagan and CMT's Kourtney Hansen, "The Big & Best of 2012" will be broadcast live from MTV's Times Square studio and on location in music venues in New York City, Boston and Nashville.