Manti Te'o -- I Was Duped ... and I'm Humiliated

Notre Dame linebacker Manti Te'o claims he's a victim who fell for someone's "sick joke" ... and he's really embarrassed over the scandal that's erupted over his not-really-dead girlfriend.

Back in September, Te'o told multiple media outlets that his girlfriend Lennay Kekua had died after a bout with cancer ... hours after his grandmother passed away. The story was so emotional, it helped catapult him to fame.

But earlier today, a story broke that Lennay was a fiction -- which means she never died because she never lived. Question is ... was Manti in on the hoax?

According to Manti ... the answer is no. The football star now says:

"This is incredibly embarrassing to talk about, but over an extended period of time, I developed an emotional relationship with a woman I met online. We maintained what I thought to be an authentic relationship by communicating frequently online and on the phone, and I grew to care deeply about her.

To realize that I was the victim of what was apparently someone's sick joke and constant lies was, and is, painful and humiliating.

It further pains me that the grief I felt and the sympathies expressed to me at the time of my grandmother's death in September were in any way deepened by what I believed to be another significant loss in my life.

I am enormously grateful for the support of my family, friends and Notre Dame fans throughout this year. To think that I shared with them my happiness about my relationship and details that I thought to be true about her just makes me sick. I hope that people can understand how trying and confusing this whole experience has been.

Fortunately, I have many wonderful things in my life, and I'm looking forward to putting this painful experience behind me as I focus on preparing for the NFL Draft."

Are you buyin' what he's sellin'?