Ljungberg has announced he's leaving his first team coaching role.
Edu told arsenal.com: "I'm a little bit sad of course because as everybody knows we are very close friends. We worked together as footballers and then we had the opportunity to work together outside the field as well.
"I remember the beautiful time we had together and I always mention to him that he was the first person to invite me to go to a dinner, and I remember Fred with his hat, hair, the style, sometimes people looked and said 'Oh Fred's a crazy guy' but he was totally the opposite and he treated me as a very close friend and we built a very nice relationship.
"I'm going to be following his future because I want to see him succeeding, because he deserves that. He is prepared to go for the next step and I am always going to follow him and support him as much as I can."