Coutinho and Firmino played together for the Reds before the former's dream move to Barca last year for a club record £142million which has yet to pay dividends.
The Brazil international has found himself out of favour at the Nou Camp and so the Catalan giants agreed to loan him out to Bayern where he is looking to revive his career.
“He told me a lot about the different Bundesliga teams.
"Some of my Brazil team-mates asked me how things are going at Bayern.
"I told them how happy I am to be there.
“I had a great welcome from my team-mates, club, fans, media and want to repay it with goals and performances on the pitch."