Or at least we thought it was a new fringe for a couple of seconds, then we realised Katy was helpfully demonstrating the perils of inadvertantly exposing your new fringe as a fake through failure to colour match your roots.
It looks like the blue hairpiece incorporates a fringe (about which we are trying not to use the phrase "bangs trauma") and some longer strands of hair designed to blend the wiglet in to her actual hair.
Sadly the latter is fighting a losing contest because if Katy's current root situation. If she'd debuted this fringe look atop freshly dyed hair she could probably have gotten away with it, but as it is, the front portion of her head is true blue through and through while the rest is a little lighter and with visible regrowth.
We're rather assuming that Katy doesn't actually give a fig about any of this, but in case you were planning on wearing a fringe wiglet it's a handy warning of the perils of not matching your colours.