The 29-year-old has moved to the West Midlands on loan from Barcelona until the end of the season, with Villa having the option to make the move permanent at the end of the temporary spell.
Coutinho and Villa manager Steven Gerrard spent two-and-a-half seasons as teammates at Liverpool and the Villa boss is well aware of the Brazilian’s talents.
Coutinho will train with his new teammates on Wednesday as Man United prepare to take a trip to Villa Park this weekend.
Gerrard said: "Philippe is currently in the process of finalising his immigration papers and we are looking forward to getting him on the training pitch with the group on Wednesday at Bodymoor.
"He is an outstanding footballer who boasts a highly impressive CV laced with plenty of elite honours.
"I am really pleased that we have been able to bring him on board and I am looking forward to working with him.
"He is a player I enjoyed playing with previously and I know the rest of the squad here at Aston Villa will benefit from his quality and experience. His presence will be invaluable given injuries and the AFCON tournament have reduced our attacking options."
Villa and Man United met in the FA Cup third round on Monday, with the Red Devils triumphing 1-0.
