Henry Russell Walter (born April 23, 1986),[1] known professionally as Cirkut, is a Canadian record producer and songwriter.

His credits include songs and albums for prominent artists including Katy Perry, Becky G, Ava Max, Nicki Minaj, Lady Gaga, R. City, the Weeknd, Kesha, Ciara, Pitbull, Britney Spears, Maroon 5, Ne-Yo, Rihanna, Adam Lambert, B.o.B, Marina and the Diamonds, will.i.am, Jungkook, Kygo and Juicy J, among others.

Walter has written and produced the Billboard Hot 100-number one singles "Part of Me", "Roar" and "Dark Horse" by Katy Perry, "Wrecking Ball" by Miley Cyrus, "Girls Like You" by Maroon 5 and "Starboy" and "Die for You (Remix)" by the Weeknd.

He co-produced the Britney Spears song "Mmm Papi" which appeared on her 2008 album Circus.

[5] He sent it as an instrumental track to Kobalt Music Group via their attorney Chris Taylor, where songwriter Nicole Morier began using it to write with Britney Spears.