The US Supreme Court has agreed to hear last-ditch legal arguments from TikTok as to why it should not be banned or sold in the US.
The US government is taking action against the app because of what it says are its links to the Chinese state - links which TikTok and its parent company ByteDance have denied.
The Supreme Court justices did not act on a request by TikTok for an emergency injunction against the law, but will instead allow TikTok and ByteDance to make their case on 10 January - nine days before the ban is due to take effect.
Earlier in December, a federal appeals court rejected an attempt to overturn the legislation, saying it was "the culmination of extensive, bipartisan action by the Congress and by successive presidents".