Coleman and Collins had been in dispute after the manager accused the defender of refusing to play for his country last month, something the West Ham player denied.
Coleman made it clear face-to-face talks would be necessary to resolve the disagreement and, after discussions in Cardiff on Wednesday afternoon, Collins was brought back on board.
The 30-year-old will provide valuable defensive cover for a decimated Wales squad missing 10 players named in the original 23-man party, including defenders Ashley Williams, Ben Davies, Adam Matthews, Sam Ricketts and Danny Gabbidon.
A statement on the Football Association of Wales website read: "Following face to face meetings this afternoon between Wales manager Chris Coleman and James Collins, the experienced West Ham defender has been called up into the Wales squad to face Macedonia and Belgium.
"Collins took part in a full training session at the Vale of Glamorgan training complex this afternoon."