Based on the press release, it appears the show is airing at 12:45 p.m. U.S. Eastern Time for only the premiere -- presumably ITV is airing special New Year's programming during the day given the odd start time.
It will air at 4 p.m. U.S. Eastern Time beginning with Episode 2, meaning "Tipping Point" gets another rest (currently off the air because of the DOND revival).
The new WOF will be a Saturday night show -- looks to be eight episodes for the first season/series. Latest season of the UK's version of "The Voice" ends Dec. 30, so ITV will have a hole to fill.
JD