Golden Boy Promotion's Showtime televised tripleheader, taking place on December 13th from the MGM Grand in Las Vegas, got beefed up with additional action.

Featured on the undercard will be two separate 10-round bouts featuring former three-time, three-division world champion Abner Mares and former welterweight world champion "Vicious" Victor Ortiz. Mares, who will fight in a featherweight bout against an opponent to be determined, will look to build on his recent victory over Jonathan Oquendo. Ortiz is looking to make a comeback statement in a welterweight bout against an opponent to be named.

Mares (27-1-1, 14 KOs) of Guadalajara, Jalisco, Mexico, and fighting out of Downey, Calif. is coming off of a unanimous decision victory over Johnathan Oquendo at MGM Grand in July. Prior to his impressive win, Mares suffered the first loss of his professional career to the hands of Johnny Gonzalez, but has since bounced back and is ready to fight. Mares found himself on the pound-for-pound list in 2013 after winning the WBC Featherweight title, adding to his accomplishments as he already held world championships at bantamweight and super bantamweight.

Ortiz (29-5, 22 KOs) is ready to show the boxing world that he still has what it takes to be great. The 27-year-old Ventura, Calif. native has made headlines in and out of the ring, not only as a fighter, but also an entertainer. A former welterweight world champion who has engaged in memorable battles against the best in the boxing business including Floyd Mayweather, Marcos Maidana, Andre Berto and Josesito Lopez. He has also crossed over into the bright lights of Hollywood as a member of the cast of ABC's hit series "Dancing With The Stars" and most recently as part of the film "Expendables 3." Now Ortiz will return to the ring for the first time since his knockout loss against Luis Collazo in January and looks to show the boxing world he's serious about another run at a world title.

"I am so happy to be back at MGM Grand after my recent win in July," said Mares. "My ultimate goal is another shot at a world championship and a win on December 13 will help me get there. I plan on putting on a great performance and showcasing my skills once again."

"I'm excited to get back into the ring," said Ortiz. "I got caught in my last fight, but I'm ready to get back to work and improve my game. I know what it takes to win and that is what I plan on doing on December 13. I'm thankful for the opportunity and looking forward to giving fans a great show."

The card will be headlined by a welterweight showdown between Amir Khan and Devon Alexander. Also, Keith Thurman faces Leonard Bundu in battle of undefeated welterweight sluggers and WBO 154-pound champion Demetrius Andrade takes on unbeaten contender Jermell Charlo.