The 1975 singer was spotted by several fans Saturday night during TS' Philadelphia stop, where he was seen taking in the view from a box seat out in the stands ... standing next to none other than Scott Swift, who was also watching his daughter and jamming out.

There are several videos and photos of them circulating on social media -- including some where they're seated ... and their faces can be seen in full view. At one point in one of these clips, you can see Scott lean in and say something to Matty. They look comfortable.

Another interesting person who was in the box with both of them ... Matty's label head, Jamie Oborne, who founded Dirty Hit -- to which MH's band, The 1975, is signed.

The 3 of them were actually seen roaming the stadium floor at one point too -- so, no doubt they were rolling together. BTW, Matty and Scott may have also been at Taylor's concert on Friday ... there are photos showing them in the same box, but in different outfits.

It's interesting ... a lot of fans saw Matty and Scott in the open, and they certainly weren't trying to lay low. Frankly, their box seats were just above a crap ton of normies below.

So, what can we make of this??? On its face ... it would seem to mean Taylor/Matty aren't hiding the fact they're seeing each other. Not just that, but they're obviously close if Matty's getting face time with her family this soon ... although, he may have already met them.

Fact is, Matty's known Taylor for years now ... and they've been painted as close friends. It's possible Matty's already met Taylor's mom and dad -- still though, it's a big development.

Pretty eventful weekend for Swifties. Not only did they get to see their idol perform some heroics on behalf of a fan watching the show ... but they got some new love life deets too.

Time will tell if Matty continues to follow Taylor on the road ... she's got a lot of dates left.