Wednesday's Southland will feature arguably the show's biggest guest star ever - and we're not just talking about celebrity status!Former NBA star Shaquille O'Neal guest-stars on Wednesday's episode as a detective who crosses paths with Officer John Cooper (Michael Cudlitz), who turns out to be a familiar face. "[His character] and I went to the Academy together and came up in the ranks together," Cudlitz tells TVGuide.com. "He went off into being a detective, and I stayed on patrol through choice. We're not great friends on the show, but we do [have some] history."Southland's back on the beat - and this time it's personalSo what brings the men together again? "A gangbanger who is pretty high up in the ranks gets taken out and there's sort of a power grab going on within the gang," Cudlitz teases. "We know a lot of these guys with outstanding warrants are going to show up at the funeral, so it brings together a lot of cops who wouldn't necessarily be together."Acknowledging that TNT's critically loved cop drama, which won a Peabody Award last week, has often shied away from doing typical TV ratings grabs, Cudlitz argues that the former Los Angeles Laker's appearance isn't just stunt casting. "It was amazing working with him. I was utterly surprised," Cudltiz says. "He was fun, he was relaxed. If the show were to continue I would love to see him pop in and out. He was fantastic.A night out with the cast of Southland"Obviously everyone's going to know it's Shaq and maybe it will draw some more eyes onto the show," Cudlitz conitinues. "But it's one of those rare moments where Southland just has fun. As the show has always treated our city with respect, it's a wonderful homage to Los Angeles. And let's not forget that Shaq is a reserve officer. He's probably the only one who belongs out there in uniform!"Check out a photo of Cudlitz and O'Neal together on the set below. Southland airs Wednesdays at 10/9c on TNT.