At first glance, this tee is pretty basic.
It features in The Power of Three and is worn with the Whistles blue jeans, UGG boots (which I must reiterate - ohgoddon'tweartheseoutsidethehouse!) the Gogo Philip necklace, watch and an un-IDed brown belt which pops up frequently in this season.
The tee is a grey marle and looks to be lightweight. From the way it hangs I think it is a soft jersey, or like, fabric. The neckline is a soft V and the sleeves capped. There's an interesting little seam detail where the tiny sleeve joins the shoulder, and no hem on the sleeve as it rolls under itself. It's a nice touch, a step up from completely bland and basic.
There's a decent chance this tee is by Allsaints given is frequency of use in Season 7.