The Dutch veteran has called time on his playing career in order to take charge at San Siro following the sacking of Massimiliano Allegri
Seedorf was heavily linked with the Rossoneri post earlier in the season as Milan struggled to find form under Massimiliano Allegri.
Allegri was relieved of his duties following Milan's shock 4-3 defeat to Sassuolo on Sunday, prompting further speculation that the Dutchman was primed to take the reins of the Serie A giants, and the Netherlands veteran confirmed on Tuesday that a deal is indeed in place for him to take on the role.
"I am here to announce that I will retire from playing after 22 years," the 37-year-old, who has been playing for Botafogo since 2012, told reporters in Brazil.
"It has been a difficult decision, but I am satisfied with what I have achieved in my career. Here at Botafogo I am happy because I leave a team who have qualified for the [Copa] Libertadores.
"I leave an improved club, especially in terms of their mentality and team spirit. Unfortunately, life as a footballer isn't eternal.
"Milan? We will meet again. This experience of the last year and a half has made me grow up a lot and will help me in my next step, as coach of Milan, who have hired me in both an elegant and correct manner.
"I like challenges and coaching Milan will be another challenge in my career. I couldn't say no to Milan after having spent 10 years there.
"The sacking of Allegri was crucial to my decision. The call from [Adriano] Galliani only came yesterday. I want to travel to Milan today. If I don't make it, then I will travel tomorrow.
"I made the decision to join Milan today but last night was a difficult night for me. But I made the right choice. I'm very happy about the opportunity Milan have given me and I'm very motivated.
"I hope that Brazil can have a memorable World Cup and the national team can honour its colours. Thank you."
Seedorf made more than 400 appearances in a stellar 10-year spell with Milan, during which he claimed two Serie A and two Champions League titles.