Key AFL forward Chris Dawes will link with Melbourne in 2013.
Collingwood on Tuesday night announced that Dawes would be traded to the Demons in exchange for a first round draft pick and a swap of later round selections.
Magpies and Demons officials met on Tuesday to lock in a deal, Collingwood confirming in a statement that the Demons would hand over picks 20 and 45 for Dawes and selection 58.
The agreement is expected to be ratified by the AFL on Wednesday.
Dawes played 71 matches for the Magpies in a career as a tall forward, having a key role in the Magpies' 2010 premiership win.
The 24 year-old played 23 matches in 2012 and kicked 16 goals but finished the campaign in difficult circumstances, playing the preliminary final against Sydney with a knee injury in a match that would turn out to be his last game for the club.
"Chris can be proud of his contribution to Collingwood. He played some good football for the club, where he has been a popular figure, and shared in the 2010 premiership," Collingwood director of football, Geoff Walsh, said in a statement.
"In his time with us, Chris always gave what he had and for that we thank him. We wish him well."
The deal was Collingwood's third of the trade period.
Former West Coast forward Quinten Lynch joined the Magpies as an unrestricted free agent two weeks ago and mid-fielder Sharrod Wellingham joined the Eagles in exchange for a first round national draft selection.
If the in-principle agreement is approved by the AFL, the Magpies will then hold picks 17, 18 and 20 in the first round of next month's national draft.