Putthipong “Billkin” Assaratanakul has been on the rise since his industry debut in 2016, as a host on the online show Love Missions. His breakthrough role came in 2019, when he played Doctor Tao in My Ambulance, where he was paired for the first time with Krit “PP” Amnuaydechkorn. The onscreen pairing proved popular, and was reprised in the 2020 coming-of-age romance series I Told Sunset about You and its second season, I Promised You the Moon, in 2021. After premiering in Thailand, the hit show was broadcast in Japan, Taiwan and the Philippines, where it received critical and popular acclaim and vaulted the two actors to international prominence. Weibo TV Series Awards (2020), Seoul International Drama Awards (2021, 2022), Asia Artist Awards (Japan, 2022) and others bestowed accolades on the series.

Aside from acting (and a bit of runway modelling), Billkin is a singer under the Billkin Entertainment label. He has released singles and contributed singing for original series, including the soundtracks for I Told Sunset About You and I Promised You The Moon. In 2023 Assaratanakul's solo concert sold out in five minutes.