Mitch Rowland
Mitchell Kristopher Rowland is an American songwriter and multi-instrumentalist, best known for his work as a touring guitarist and for co-writing songs on all three of Harry Styles's solo albums. "Watermelon Sugar", a song he co-wrote with Styles, Tyler Johnson, and Thomas Hull, was nominated for and won Best Pop Solo Performance at the 63rd Annual Grammy Awards in 2021. Rowland, along with Styles, Johnson, and Hull, also won the Brit Award for Song of the Year for "Watermelon Sugar" at the 2021 Brit Awards. Description above from the Wikipedia article Mitch Rowland, licensed under CC-BY-SA, full list of contributors on Wikipedia.
Filmography
The Tonight Show Starring Jimmy Fallon
Jimmy Kimmel Live!
Harry Styles. One Night in Manchester.
Harry Styles: Behind the Album
Harry Styles: Behind the Album - The Performances
Harry Styles: Live at Coachella
Harry Styles - One Night Only in New York
Harry Styles at the BBC
Harry Styles: Live in Manchester