| Year | Song | Artist | Album | Role | Ref. |
| 2002 | "Where Is My Boy?" | Faultline | Your Love Means Everything | Featured artist · co-writer | |
| "Your Love Means Everything Part 2" |
| "Gold in Them Hills" | Ron Sexsmith | Cobblestone Runway | Piano | |
| 2003 | "Sliding" | Ian McCulloch | Slideling | Backing vocals | |
| "Arthur" | Backing vocals · piano |
| "See It in a Boy's Eyes" | Jamelia | Thank You | Co-writer · backing vocals · piano | |
| 2004 | "Everybody's Happy Nowadays" | Ash | "Orpheus" | Backing vocals | |
| "Do They Know It's Christmas?" | Band Aid 20 | — | Featured artist | |
| 2005 | "What Ever Happened to the Cosmic Kid?" | Various | The Electric Institute | Co-writer | |
| 2006 | "All Good Things (Come to an End)" | Nelly Furtado | Loose | |
| "In the Sun" | Michael Stipe | In the Sun (Gulf Coast Relief) | Featured artist | |
| "Beach Chair" | Jay-Z | Kingdom Come | Featured artist · producer | |
| 2007 | "Homecoming" | Kanye West | Graduation | Featured artist · co-writer | |
| 2009 | "Want" | Natalie Imbruglia | Come to Life | Co-writer · keyboards | |
| "Dove of Peace" | Brüno Gehard | Brüno | Featured artist | |
| 2010 | "Most Kingz" | Jay-Z | — | |
| "Me and Tennessee" | Gwyneth Paltrow · Tim McGraw | Country Strong | Writer | |
| "Halo" (Live) | Beyoncé | Hope for Haiti Now | Featured artist · piano | |
| 2012 | "I Don't Want You to Die" | The Flaming Lips | The Flaming Lips and Heady Fwends | Featured artist | |
| "Viva la Vida" (Live) | — | 12-12-12: The Concert for Sandy Relief | |
| "Losing My Religion" (Live) | Michael Stipe |
| "Us Against the World" (Live) | — |
| 2014 | "Wish I Was Here" | Cat Power · Coldplay | Wish I Was Here | Writer | |
| "Invictus Games Anthem" | Various | — | |
| "Do They Know It's Christmas?" | Band Aid 30 | Featured artist | |
| 2015 | "True Believer" | Avicii | Stories | Co-writer · backing vocals · piano | |
| "Every Day's Like Christmas" | Kylie Minogue | Kylie Christmas | Co-writer · backing vocals | |
| 2016 | "Electricity" | David Brent | Life on the Road | Featured artist | |
| 2017 | "Homesick" | Dua Lipa | Dua Lipa | Co-writer · backing vocals · piano | |
| 2018 | "Keep Talking" | Rita Ora | Phoenix | Unknown | |
| 2019 | "Joyride" | Big Sean | — | Featured artist | |
| "Someone That Loves You '19" | Izzy Bizu | Glita | |
| "Heaven" | Avicii | Tim | Featured artist · co-writer · keyboards | |
| "Stratosphere" | Beck | Hyperspace | Backing vocals | |
| 2020 | "Sondela Forever" | Muzi | — | Co-writer · producer | |
| "Times Like These" | Live Lounge Allstars | Featured artist · piano | |
| "Monsters You Made" | Burna Boy | Twice as Tall | Featured artist · co-writer | |
| 2021 | "Red Love" | Emmanuel Kelly | Your Story | Executive producer | |
| "Love Is a Mighty River" | Merry Clayton | Beautiful Scars | Co-writer | |
| 2022 | "Across the Oceans" | Mamak Khadem | Remembrance | Featured artist · piano | |
| "Riptide" | The Chainsmokers | So Far So Good | Co-writer | |
| 2023 | "Queen" | Muzi | uMuzi | Featured artist | |
| "Astronaut" | Griff | Vert1go Vol. 1 | Piano | |
| 2024 | "Over You" | Jacob Collier · Aespa | Djesse Vol. 4 | Featured artist | |
| "Raze the Bar" | Travis · Brandon Flowers | Times | Backing vocals | |
| "Wandering Talk" | Orlando le Fleming · Romantic Funk | Wandering Talk | Featured artist | |
| 2025 | "Ma Meilleure Ennemie" (Extended Version) | Stromae · Pomme · Coldplay | Arcane League of Legends: Season 2 | Co-writer | |
