Bengals' Wallace Gilberry: I Had to Help That Family ... I Saw Their Faces

He's the NFL lineman who surprised a family of 7 in a Target store by picking up the check for a PS4 ... and now Bengals star Wallace Gilberry is finally explaining why he did what he did.

Gilberry's story made national news when someone shot a pic of the 270-pounder approaching the random family Monday night and offering to buy holiday gifts for the kids.

So ... why?

"I just went to Target to get some clippers to trim my beard and I saw a family with a dad, wife and five or six kids. The kids were looking at the electronics and I could tell by the mom's face that she was upset about telling the kids they wouldn't be able to afford what they wanted."

"I went up to the family and asked them if they would mind if I bought the kids whatever they wanted. They said that would be so great ... the dad said he was starting a new job and money was tight."

So, Gilberry bought a PS4 and a bunch of video games -- "One of the kids was really excited about a game called Minecraft. I don't even know what that is, but he went crazy."

In the end, Gilberry dropped somewhere close to $800 ... but says it's not about the money.

"One thing about me is that I grew up with my shirt on my back and that's it. Money doesn't define me. If I have a million dollars, I'm going to try to help a million people."