The pop star and NFL'er surfaced separately on the East Coast Saturday -- with TS popping up in the Big Apple alongside Blake Lively and Ryan Reynolds ... with the trio walking through the streets of NYC looking stylish.

Just over the bridge ... Travis and some other Chiefs players, including Patrick Mahomes, were checking into their hotel in New Jersey -- which is where they'll play Sunday's game.

As we reported ... Taylor is expected to show up to MetLife Stadium to once again watch TK's big match against the Jets -- a game that'll be televised on NBC during Sunday Night Football, and which will undoubtedly garner more eyeballs than last week did.

Considering she's in town ... it's all but guaranteed we'll be watching her root from the sidelines. The question now is -- will Taylor's in-game visits become a regular thing???

We know she and Trav hit the town in KC last week ... and their gallivanting caused quite a stir in the city. In this neck of the woods, though -- that'll be amplified by at least 10 ... with tons of paparazzi crawling all over the place, not to mention adoring fans left and right.

If this does, in fact, become a tradition as these 2 explore their relationship ... you also gotta wonder if we'll see added PDA as time goes on. We already saw them cozying up during an after-party -- and now that the cat's outta the bag, perhaps more is on the horizon.

There's been some speculation this all might be a PR stunt -- but now ... it feels real.

Remember, we were told Taylor's team is still working out security logistics for MetLife ... meaning, she won't be able to just slip in all casual-like the way she did last week.

With all this in mind, it probably goes without saying -- if we happen see Taylor and Travis out and about at all this weekend ... it'll undoubtedly be another frenzy and then some.