ˌɔn mˈeɪ θˈɜːtiːn, tˈuː θˈaʊzənd twˈɛnti, ɪt wʌz ɹᵻvˈiːld ðæt sˈækjʊɹɹˌaɪ hæd ɹˈɪʔn̩ ðə sˈɔŋ "smˈaɪl", wˌɪtʃ wʊd biː sˈʌŋ baɪ dʒˈɑːni ænd ɐsˈoʊsɪˌeɪts ˈɑːɹɾɪsts spˈɛʃəl jˈuːnɪt "twˈɛnti twˈɛnti", ðæt ɪŋklˈuːdz æɹˈæʃi, kˈættˈʌn, vˈiː sˈɪks, kˈɪŋ ænd pɹˈɪns, sˈɪks tˈoʊnz ænd ˈʌðɚz, æz pˈɑːɹt ʌv dʒˈɑːniz tʃˈæɹᵻɾi æktˈɪvᵻɾi "smˈaɪl ˌʌp pɹˈɑːdʒɛkt".
On May 13, 2020, it was revealed that Sakurai had written the song "Smile", which would be sung by Johnny & Associates artists' special unit "Twenty★Twenty", that includes Arashi, KAT-TUN, V6, King & Prince, SixTones and others, as part of Johnny's charity activity "Smile Up Project".