11:49 AM PT -- New photos have surfaced showing Manti and Alexandra sitting on Santa's lap together sometime around Christmas.

Alex also posted a photo on November 16, in which she thanked Manti for giving her a couple of leis, which she hung in her car.

The dates are consistent with the story Manti is telling friends.

Manti Te'o quietly began dating an actual living, breathing female human being ... shortly after he learned "Lennay Kekua" had died from cancer ... and the rebound chick is HOT ... TMZ has learned.

Sources close to Manti tell us ... the Notre Dame star met Alexandra del Pilar the weekend of November 10 -- when Notre Dame played Boston College.

Alexandra, 21, is a student at St. Mary's College in Indiana -- which is close to Notre Dame.

We're told Alexandra and Manti dated for nearly 2 months, but broke up recently.

There are rumors swirling that Manti created a fictitious GF to take the pressure off him from teammates and others who felt he should be dating, but his relationship with a real woman calls those rumors into doubt.