According to fightersonlymagazine:

American Top Team welterweight Thiago Alves has been matched with John ‘Doomsday’ Howard for UFC 124 on December 11th.

The fight was first reported by MMA Junkie and has since been confirmed to Fighters Only by sources close to the bout.

Thiago "Pitbull" Alves (17-7)
Loss Jon Fitch - Decision (Unanimous) UFC 117
Loss Georges St. Pierre - Decision (Unanimous) UFC 100
Win Josh Koscheck - Decision (Unanimous) UFC 90
Win Matt Hughes - TKO (Flying Knee and Punches) UFC 85

John "Doomsday" Howard (14-5)
Loss Jake Ellenberger - TKO (Doctor Stoppage) UFC Versus Live 2
Win Daniel Roberts - KO (Punch) UFC Versus Live 1
Win Dennis Hallman - KO (Punches) UFC TUF 10 Finale
Win Tamdan McCrory - Decision (Split) UFC 101

HT: SSreporters, photo via cbssports.com