Michael Phelps Returns for One Last Swim in Under Armour's Haunting New Ad

Bearded champion preps for Rio

Michael Phelps has been an Under Armour endorser since 2010, but of course, he's only truly in the spotlight quadrennially, during the Olympics. Now 30 years old, the world's greatest-ever swimmer is making one final Olympic push—for the Rio Games this August.