Ultimate Fighting Championship (UFC) hit Las Vegas, Nevada, today (March 27, 2012) to announce its upcoming UFC 146: "Dos Santos vs. Overeem" event, which is scheduled for May 26 at the MGM Grand Garden Arena.

And the big boys crashed the party.

That includes Junior dos Santos, who smiled broadly all throughout the proceedings while toting his heavyweight championship around. That is until it came time to have his staredown with Alistair Overeem, who will attempt to snatch the belt away over the Memorial Day weekend.

For the first time in company history, the entire main card will be comprised of heavyweight bouts. That's why Frank Mir vs. Cain Velasquez and Roy Nelson vs. Antonio Silva were also in attendance. You can see those respective staredowns after the jump.

For a complete rundown of the UFC 146 press conference with all the relevant notes and quotes click here. And to stay up to date on all things UFC 146 be sure to hit up our event archive right here.