Liverpool boss Brendan Rodgers has insisted Mario Balotelli will not be going out on loan in the January transfer window.
The 32-year-old striker recently ended a spell with Toronto FC in Canada and has signed for the Seasiders after training with the club this week.
Earnshaw will miss Saturday's Sky Bet Championship home clash against Huddersfield as international clearance was not received in time, but is expected to make his debut at Bolton on Tuesday.
The arrival of the Wales international will give Blackpool some much-needed fire-power as they are just six points clear of the drop zone.
"This is a great opportunity for me to play some games and give the fans something to cheer about before the end of the season," he told the club's official website.
"Mentally I feel really fresh because I've been dying to go, so signing here is going to be exciting.
"I'm hoping I can come here and give the fans some goals and somersaults, give them what I've given to every other team."