The mid-to-late 2000s saw the arrival of several new dance-pop artists, including Rihanna, Kesha, Katy Perry and Lady Gaga. This period in time also saw dance-pop's return to its more electronic roots aside from its disco ones, with strong influences of synthpop and electropop. Lady Gaga is frequently considered as one of the pioneers of this evolution, notably with her singles "Just Dance" and "Poker Face" which were heavily influenced by synthpop and electropop. Rihanna's singles in the dance-pop genre, including "Don't Stop the Music" and "Disturbia", contained electronic influences, the former of which has elements of house music, the latter electropop. Kesha's debut single, "Tik Tok", was also highly electronic in style and employed a video game beat. Katy Perry's "Hot N Cold" (2008), "California Gurls" (2010), and "Firework" (2010), which were major commercial hits, also showcased influences of electropop and house music.