2:40PM BST 05 Aug 2011
Roberto Mancini has been following Pantilimon since he impressed against City in two Europa League meetings last season.
Manchester City beat off competition from Inter Milan and Arsenal to sign the 24 year-old.
Mancini was in the market for a back-up to Hart after Shay Given completed his move to Aston Villa.
City, who make their debut in the Champions League after finishing third last season, have also signed left-back Gael Clichy from Arsenal, Argentina striker Sergio Aguero from Atletico Madrid and defender Stefan Savic from Partizan Belgrade.
Mancini also hopes to bring in "another two or three players" before the transfer deadline at the end of the month.