Shawn Porter has called on a middleweight champion to help him prepare for his upcoming showdown with Errol Spence Jr.

Porter has enlisted Demetrius Andrade for what figure to be some spirited sparring sessions as he winds down training camp for his welterweight title unification fight September 28 versus Spence. At 6-feet-1, the left-handed Andrade is even bigger than the 5-feet-10 Spence.

Porter expects his work with Andrade to help him handle Spence’s size and strength in what will be a grueling 147-pound championship match at Staples Center in Los Angeles.

“I had spoken to ‘Boo Boo’ back in maybe like May or June, and he told me that he would be there for me,” Porter said about Andrade during the most recent episode of “The PBC Podcast” on premierboxingchampions.com. “Demetrius Andrade, we’ve known each other since we were 16. We have a fantastic relationship. We’re like distant brothers.

“You know, so he knows that I’m against the fight of a lifetime, and he wants to be there to support me. He’s gonna meet us in [Washington, D.C.] over the next two weeks, and he’s gonna spar with me in D.C. and get me ready for this fight. So, we haven’t sparred just yet, but we do have him committed to come and train with me in the next two weeks.”

Andrade (28-0, 17 KOs), the WBO 160-pound champion, doesn’t have a fight scheduled, thus he figures to be at least slightly heavier than if he, too, were training for a fight.

Porter already has sparred during this training camp against bigger, stronger opposition, most notably former WBC super middleweight champ David Benavidez. Phoenix’s Benavidez (21-0, 18 KOs) is scheduled square off against Anthony Dirrell (33-1-1, 24 KOs), of Flint, Michigan, for the WBC 168-pound title on the Spence-Porter undercard.

“One-hundred percent, you could feel all of the strength and size that guy has,” Porter said of the 6-feet-2 Benavidez, who’s right-handed. “It was interesting trying to push him back, trying to be aggressive against him, also using my feet to get him out of position. You know, a lot of the tactics we expect to use against Errol Spence. I think using them against a guy that big, I think on top of building your confidence, I think it’s just another way to recognize what works and what doesn’t work against another world-championship athlete.”

The bout between Spence (25-0, 21 KOs), of DeSoto, Texas, and Porter (30-2-1, 17 KOs), of Akron, Ohio, will headline a FOX Sports Pay-Per-View show two weeks from Saturday night. They’ll fight for Spence’s IBF welterweight title and Porter’s WBC championship.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.