The Tyneside-based club have been taking a look at the young attacker since pre-season, having brought him to the club as a trialist.
Indelacio featured in Newcastle Under-23s fixtures in pre-season and also caught the eye of many with a spectacular goal in training.
The Magpies have now extended the 23-year-old Frenchman’s terms until the end of the season after monitoring him over a trial period.
The number 10 can now play games for Newcastle’s Under-23s side this season.
Indelacio previously plied his trade for Ligue 1 club St. Etienne’s youth set-up but left the club after issues.
The Frenchman then had a stint with Australian club Fraser Park FC, who he left following the expiration of his contract.
Indelacio will now be hopeful of gradually making his way back into European football, with Newcastle opening him a door.