Perttu Päivö Kullervo Kivilaakso is a cello player for Finnish band Apocalyptica. Like fellow band members Eicca Toppinen and Paavo Lötjönen, he attended Sibelius Academy in Helsinki.

Kivilaakso won third place in the second International Paulo Cello Competition in 1996 at age 18. Shortly afterward, he attained a lifetime chair in the Helsinki Philharmonic Orchestra,[4] where his father, Juhani, is also a cellist. He was on indefinite leave while touring with Apocalyptica, but left for good in 2007.

Kivilaakso has also composed music for the video game Max Payne 2: The Fall of Max Payne, a few documentary films, as well as many original compositions for Apocalyptica, including "Conclusion", "Farewell" and "Beautiful".

His first opera, Indigo, composed with his Apocalyptica bandmate Eicca Toppinen, was premiered at the Finnish National Opera on 22 January 2016. The opera tells "a story of an omnipotent, multinational company and a search for happiness".