Park Bo Young and Ji Chang Wook showed their support for SPEED's debut.
Both actors had featured in SPEED's music video for "Sad Promise". Park Bo Young wrote on her official homepage, "It's coming out today, everyone. I didn't watch it properly yet either. Everyone, please look forward to it like I am, and cheer them on."
Ji Chang Wook tweeted, "SPEED's music video is out. Please have fun watching it ^^," later adding, "Did everyone watch SPEED's music video? Part 2 will come out soon as well. Please show a lot of love for both the song and the music video! Have a good day!"
The music video for "Sad Promise" and "It's Over" deal with the Gwangju Democratization Movement. The dramatic music video for "Sad Promise" is reported to have cost over 750 million won (~$706,000 USD) to produce and features actors Park Bo Young, Ji Chang Wook, Ha Seok Jin, and A Pink's Na Eun as well as Choi Ji Yeon, Kim Young Ho, Choi Minah, and Jung So Young.