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Cassia O'Reilly

Irish singer-songwriter

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Source updated June 3, 2026

Cassia O'Reilly (known professionally as Cosha and formerly known as Bonzai) is an Irish singer-songwriter and music producer.

01Background

O'Reilly was born in Indiana, United States, and raised in Ireland, between County Wicklow and Dublin. Her African-American descent mother was a singer and her Irish father was a drummer. She moved to London at age 17.

02Career

O'Reilly has worked with Eg White, Mura Masa and Rostam and Justin Raisen and toured with Flume.

03Discography

Albums

*Mt. Pleasant* (2021) (as Cosha)
No.	Title	Writer(s)	Producer(s)	Length
1.	"Berlin Air"	Cassia O'Reilly	Mura Masa Cosha Brett Shaw	3:54
2.	"No Kink In The Wire"	O'Reilly Jacob Vetter Johan Hugo	Cosha JATA Hugo Koreless	5:30
3.	"Do You Wanna Dance?"	O'Reilly Rostam Batmanglij	Rostam	3:26
4.	"Lapdance from Asia" (featuring Shygirl)	O'Reilly Blane Muise Zack Sekoff	Mura Masa Cosha Shaw Koreless	3:28
5.	"Run the Track"	O'Reilly Batmanglij	Rostam Cosha	3:00
6.	"Tighter" (featuring Coby Sey)	O'Reilly Alexander Crossan Coby Sey Emile Haynie Loraine James Patrik Berger	Cosha Berger Mura Masa James	4:09
7.	"Hot Tub"	O'Reilly Crossan Nate Huff Tobias Laust Hansen Vilhelm Tiburtz Strange Villads Tyrrestrup Øster	Cosha Mura Masa	2:50
8.	"Bad Luck"	O'Reilly Haynie	Cosha Mura Masa Haynie	3:45
Total length:				30:05

EPs

MurMurs (2024) (as Cosha)

All tracks are written by O'Reilly.

No.	Title	Producer(s)	Length
1.	"Fire Me Up"	Blacknoi$e O'Reilly Gabe Acheson Sekoff	3:51
2.	"Royah & Halia"		0:54
3.	"Sun Back"	Mura Masa O'Reilly Acheson James Massiah	4:14
4.	"Relish"	Mura Masa O'Reilly Acheson Sam Knowles	3:32
5.	"Want You Back"	1Mind O'Reilly Acheson Mura Masa Sekoff	3:35
6.	"Perfect"	1Mind O'Reilly Mura Masa Sekoff	3:35
7.	"MurMurs Interlude"	Mura Masa O'Reilly	2:17
8.	"Glow"	O'Reilly Acheson Mura Masa Sekoff	4:43
Total length:			26:25

Mixtapes

*R.I.P. Bonzai* (2018) (as Cosha)
No.	Title	Writer(s)	Producer(s)	Length
1.	"Do You Wanna Dance?"	Cassia O'Reilly Rostam Batmanglij	Rostam	3:26
2.	"When U Call"	O'Reilly Jeff Gitelman	Mura Masa Gitelman	1:44
3.	"Bladerunnin'"	O'Reilly Hugo	Mura Masa Hugo Tom Tripp	3:27
4.	"LUV"	O'Reilly Batmanglij	Rostam	3:08
5.	"Brake Lights" (featuring NAO)	O'Reilly Crossan Neo Jessica Joshua Daniel Traynor Francis White	Mura Masa	2:20
6.	"Honey"	O'Reilly Crossan Daniel Eisner Harle	Mura Masa Danny L Harle	3:31
7.	"Rare Fruit"	O'Reilly Gitelman	Mura Masa Gitelman Kevin Tuffy	3:26
8.	"Sad Train Beat"	O'Reilly Hugo	JATA Hugo	3:53
9.	"Jaw Bone"	O'Reilly Hugo	JATA Hugo Mura Masa	3:11
10.	"U Better"	O'Reilly Traynor	Mura Masa GRADES	1:52
11.	"This Life"	O'Reilly Traynor	Mura Masa GRADES	4:29
12.	"Flacko"	O'Reilly James Harmen Stack	Mura Masa Jim-E Stack Kai Campos	4:35
Total length:				39:02

Extended plays

*Royah* (2015) (as Bonzai)
No.	Title	Writer(s)	Producer(s)	Length
1.	"Doses"	Cassia O'Reilly Jonathan Calvert	Calvert	3:02
2.	"Nikka"	O'Reilly Calvert	Calvert	3:18
3.	"Skhokho"	O'Reilly Crossan	Mura Masa	2:40
4.	"Noise"	O'Reilly Calvert	Calvert	3:47
Total length:				12:47

*Lunacy* (2016) (as Bonzai)
No.	Title	Writer(s)	Producer(s)	Length
1.	"I Did"	Cassia O'Reilly Jonathan Calvert	John Calvert	3:09
2.	"Bodhran"	O'Reilly Thomas Calvert	Redinho	2:49
3.	"2B"	O'Reilly Alexander Crossan	Mura Masa	2:53
4.	"Ding Ding Ding"	O'Reilly Crossan	Mura Masa	1:41
5.	"Cruel"	O'Reilly Rebecca Louise Jones J. Calvert	Calvert	3:24
Total length:				13:56

*Sleep Hungry* (2016) (as Bonzai)
No.	Title	Writer(s)	Producer(s)	Length
1.	"Daniel Gets It Wrong"	Cassia O'Reilly Jonathan Calvert	John Calvert	2:01
2.	"No Rest"	O'Reilly Calvert	Calvert	2:54
3.	"Ravemeister"	O'Reilly Calvert	Calvert	0:26
4.	"Stepping"	O'Reilly Calvert	Calvert	2:29
5.	"Kassi"	O'Reilly Calvert	Calvert	2:59
6.	"Faze"	O'Reilly James Luke Wood	Royce Wood Junior	3:38
7.	"Lights On"	O'Reilly Alexander Crossan	Mura Masa	2:43
8.	"Sick 'Em"	O'Reilly Calvert	Calvert	3:12
9.	"Where Are U Now"	O'Reilly Crossan Oliver Roddigan Om'Mas Keith	Mura Masa Cadenza	3:52
Total length:				24:14

Singles

As lead artist

"I Did" (2016) (as Bonzai)
"I Feel Alright" (2017) (as Bonzai)
"Do You Wanna Dance" (2018) (as Cosha)
"Luv" (2018) (as Cosha)
"Flacko" (2018) (as Cosha)
"No Kink in the Wire" (2020) (as Cosha)
"Berlin Air" (2020) (as Cosha)
"Lapdance from Asia" (2021) (as Cosha, featuring Shygirl)
"Tighter" (2021) (as Cosha, featuring Coby Sey)
"Run the Track" (2021) (as Cosha)
"Sun Back" (2023) (as Cosha)
"Want You Back" (2023) (as Cosha)
"Fire Me Up" (2024) (as Cosha)
"MurMurs Interlude" (2024) (as Cosha)

As featured artist

"What If I Go?" (2016) (Mura Masa featuring Bonzai)
"Nuggets" (2017) (Mura Masa featuring Bonzai)
"Till the World Falls" (2018) (Nile Rodgers & Chic featuring Mura Masa, Cosha and Vic Mensa)
"Thicc" (2023) (Shygirl featuring Cosha)

Songwriting credits

"Porsche" (2017) (Charli XCX featuring MØ)
"Unfold You" (2021) (Rostam)
"Shlut" (2022) (Shygirl)
"Coochie (a bedtime story)" (2022) (Shygirl)
"Wildfire" (2022) (Shygirl)
"Crush" (2023) (Shygirl, featuring Erika de Casier)
"Woe (I See It From Your Side) (Björk Remix)" (2023) (Shygirl)
"Playboy/Positions" (2023) (Shygirl)
"rep 4 me" (2024) (Mura Masa)

Watch videos about Cassia O'ReillyExplainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article “Cassia O'Reilly”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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