The broadcaster quietly began testing Sky Sports on the service last week, inviting customers to trial it ahead of a new year launch.
Now TV has been active since July, but until now has only shown movies. However, Sky has recently ramped up marketing for the offering, which allows customers to stream video via a number of devices, including iPads, smartphones and the Xbox at a cost of £15 a month, after a discounted introductory period.
A pay-per-view option was offered on launch and recently withdrawn, although Sky has said it will re-introduce it next year.
A Sky spokesman said sports will be offered on Now TV early in the new year, but did not comment on pricing.
The service would have much of the sports content that Sky offers via satellite TV, and would increase its potential customer base in the face of increasing competition from BT, which is launching a sports channel next summer.