In the drama, Matsu is in charge of playing the first violin, Matsuda plays the second violin, Mitsushima plays the cello while Takahashi plays the viola. However, all of them did not know how to play these musical instruments prior to filming this drama so they had to learn from scratch. With regard to the scenes where they have to play the musical instruments, Matsu admitted that she had tried her best to learn how to play the violin but she finds that it probably does not like her that much so she doesn't feel like she is doing well. In response to this, Matsuda said that Matsu is getting so good at the violin that he feels a lot of stress and pressure from her. He also revealed that when Matsu is getting too absorbed in the playing, she tends to stick out her chin which she said that she had given up trying to fix this problem even though she had been reminded of this many times since the filming started.
As for Mitsushima, she revealed that their music coach suggested that they should talk to their musical instruments every day so as to get more familiarised with it. In addition, she heard that the cello is modelled after a woman's body so she had a lot of fun caressing the instrument's curves at home. Mitsushima admitted sheepishly that she's a very troublesome and stubborn person so she's very thankful that her co-stars accept her for who she is and treat her very gently.
As for Takahashi, he commented that he feels as if he is lagging behind the rest when it comes to playing the viola. Especially since the viola does not play the main melody which is performed on the violin or cello, his character in the drama is somewhat seen as subservient to the others. He even cited the fact that the violin and viola are "older" than the viola as the two instruments were made in the 1700s while the latter only came into existence in the 1900s. Despite his lack of confidence in his playing abilities, Mitsushima praised Takahashi for being a guy who knows women well and does things naturally to please them.
When asked about if they would eat fried chicken with lemon juice squeezed onto it which is featured in one of the scenes in the first episode, Matsu said that she doesn't do it while Mitsushima would add the lemon juice just before she is about to eat it. Takahashi said that he will go along with the preference of the person who he is eating the dish with which led Mitsushima and Matsu to tease him for being a man who knows the mentality of women well. As for Matsuda, he said that he is OK with it either way.
Sources: Oricon / Sanspo / Sponichi / Modelpress