| Name | Character | Episodes |
|---|---|---|
| Steve Pemberton | Bill Grundy | 1 |
| Adam Brody | Jack Lemmon | 1 |
| Rupert Grint | Gustl | 1 |
| Aidan Gillen | Timothy Leary | 1 |
| James Purefoy | Billy Wilder | 1 |
| Gemma Arterton | Marilyn Monroe | 1 |
| Robbie Coltrane | Orson Welles | 1 |
| Dougray Scott | Arthur Miller | 1 |
| Alex Pettyfer | Tony Curtis | 1 |
| Eddie Marsan | Bob Dylan | 1 |
| Jack McBrayer | Andy Warhol | 1 |
| Anna Maxwell Martin | Agatha Christie | 1 |
| David Threlfall | Samuel Beckett | 1 |
| Hugh Coles | Junior Police Officer | 1 |
| Natasia Demetriou | Agnieszka | 1 |
| Katherine Parkinson | Ange | 1 |
| Mark Addy | Les Dawson | 1 |
| Martin Compston | Midge Ure | 1 |
| Jessica Barden | Barbra Streisand | 1 |
| David Suchet | Salvador Dali | 1 |
| John Bradley | Young Les Dawson | 1 |
| James Fleet | The Professor | 1 |
| Con O'Neill | Tony | 1 |
| Robert James-Collier | Col. Archie Christie | 1 |
| Paul Ritter | Dave | 1 |
| Iwan Rheon | Adolf Hitler | 1 |
| Adrian Scarborough | Chief Inspector Danders | 1 |
| Katherine Ryan | Joan Rivers | 1 |
| Ben Chaplin | Cary Grant | 1 |
| Kayvan Novak | Freddie Mercury | 1 |
| Cavan Clerkin | Cabbie | 1 |
| Paul Kaye | Shep Gordon | 1 |
| Noel Fielding | Alice Cooper | 1 |
| Jack Whitehall | Marc Bolan | 1 |
| Dustin Demri-Burns | Josef | 1 |
| Dustin Demri-Burns | Francis Rossi | 1 |
| Steve Oram | Brian | 1 |
| Mark Bonnar | Billy | 1 |
| Danny John-Jules | Don King | 1 |
| Paterson Joseph | Chuck D | 1 |
| David Avery | Freddie Mercury | 1 |
| Rufus Jones | Elton John | 1 |
| Felicity Montagu | Paula Strasberg | 1 |
| Pearl Mackie | Kay | 1 |
| Daniel Mays | Mike Housego | 1 |
| Philip Glenister | Kev Wells | 1 |
| Margaret Clunie | Marcie | 1 |
| Jonas Armstrong | Bob Geldof | 1 |
| Luke Treadaway | David Bowie | 1 |
| Lucian Msamati | Herbert Muhammed | 1 |
| Florence Hall | Klara | 1 |
| Adrian Edmondson | Leslie Conn | 1 |
| Abdul Salis | Flavor Flav | 1 |
| David Haig | George Frideric Handel | 1 |
| Frank Skinner | Johnny Cash | 1 |
| Isy Suttie | Jean Sexton | 1 |
| Marcia Warren | Grant's Mother | 1 |
| Bill Paterson | Sir Arthur Conan Doyle | 1 |
| Henry Goodman | Grant's Father | 1 |
| Paul Putner | Howard | 1 |
| Steve Edge | Barry | 1 |
| Vincent Franklin | Alexander | 1 |
| Tim Stern | Auctioneer/Journalist | 1 |
| Nick Mohammed | Horace Lambardi | 1 |
| Noel Clarke | Muhammad Ali | 1 |
| Celeste Dodwell | Nancy Neele | 1 |
| Lewis Macleod | Voiceover Artist | 1 |
| Rich Hall | Jimmy Gould | 1 |
| Kerry Shale | Hotel Manager | 1 |
| Vincent Londez | Boris Roussimoff | 1 |
| David Newman | Franz Schultz | 1 |
| Bob Cryer | Pascal | 1 |
| Anthony Atamanuik | Donald Trump | 1 |
| Nicola Reynolds | Landlady | 1 |
| Lily Frazer | Today Programme Makeup Artist | 1 |
| Tanya Franks | Becca | 1 |
| Zephryn Taitte | Anthony | 1 |
| Mike Wozniak | LeRoy Neiman | 1 |
| Rosie Cavaliero | Dorothy L Sayers | 1 |
| Rachel Bright | Christine Whitehead | 1 |
| Seb Cardinal | Rick Parfitt | 1 |
| Toby Williams | Mike | 1 |
| Alex Beckett | J-J | 1 |
| Lauren Socha | Amy | 1 |
| Frankie Fox | John Lydon | 1 |
| Jessica Gunning | Border Officer | 1 |