Haley Lu Richardson as Hadley Sullivan

Ben Hardy as Oliver Jones

Rob Delaney as Andrew Sullivan

Katrina Nare as Charlotte

Jameela Jamil as Narrator (voice)

Tom Taylor as Luther Jones

Dexter Fletcher as Val Jones

Sally Phillips as Tess Jones

Vivian Gwaspari as Headphones Girl

Jordan Frazier as Gate Agent Jenny

Tracy Wiles as Mrs. O'Callaghan

Philip Bird as Mr. O'Callaghan

Ibinabo Jack as Bridesmaid Shanti

Jessica Ransom as Bridesmaid Bertie

Doña Croll as Hat Lady Elizabeth

Leigh Quinn as Bridesmaid Jasmine

Stephan Boyce as Monty

Kerry Howard as Maid of Honour Violet

Anthony Warren as Heathrow Taxi Driver

Andromeda Godfrey as Cate Sullivan

Buddy Powell as Kid Oliver

Jasper Hawes as Kid Luther

David Rubin as Dr. Doyle

Sunil Patel as Chain Mail Guest

Sam Booth as Reverend

George Keeler as Flower Vendor

Emily Cordell as Teen Girl

David Langham as UK Border Officer

Angus Kennedy as Thicker

Jayda Eyles as Young Hadley

Paul Lacoux as Earnest Man

Ione Brown as Female Friend