The defender’s £26million switch from Sevilla was officially rubber-stamped on Wednesday as the Brazilian became the club’s third signing of the summer.
Coutinho, his fellow Brazilian, sealed a £17.2m permanent move from Barcelona last month after spending the second half of the season at Villa Park on loan.
Carlos holds the playmaker in high regard, explaining: “Coutinho, he is a phenomenon and a great footballer.
“To share the pitch with him, share the game with him, I think it will be fantastic.
“Coutinho, in fact, I spoke to him on the phone, he congratulated me on being here and being with him."
Carlos, who has signed a four-year contract, also played alongside Villa midfielder Douglas Luiz at last year’s Tokyo Olympics and added: “The two of us had the pleasure of winning the gold medal together.
“I'm really happy about this, the two players are fantastic and, as I've said, when I see them we can start working together.”
The centre-back, who won the Europa League with Sevilla in 2020, admitted the lure of the Premier League had been a big attraction for moving to Villa.
He said: “With all the countries I’ve passed through, the teams I have played for across Europe, I’ve always adapted really quickly
“I have competed in all these countries, played lots of games. I am on a new stage now and the truth is, as you have experience in three different countries, you can bring it with you.
“I hope with the experience I have I can impress the club and my team-mates and we can achieve great things.
He added: “I'm very happy, not only me, but my family and my kids.
“It's something we were really waiting for and we really wanted to do this negotiation. Now that we're here, we are really happy.”
“We are really looking forward to it. I'm a person who always looks for, and wants to achieve something more.
“Since I spoke to the club and my agent, we knew the objectives of the club. We know where we want to get to and that's something that made me excited to come here.”