Lived in New York in the 1960s.
When a publicity photo of Guest and his co-stars from This Is Spinal Tap (1984) ran in Rolling Stone magazine, Jamie Lee Curtis saw the picture, fell in love and gave her phone number to Guest's agent. They dated and eventually married.
His character from This Is Spinal Tap (1984), Nigel Tuffnel, is partially a spoof of British rocker Jeff Beck
Has two adopted children, Annie Guest (December 1986) and Thomas (March 1996). Under the terms of the letters patent that created the Barony of Haden-Guest, they cannot inherit the title, but they can use the courtesy title of the Honourable before their first names.
Half-brother of journalist Anthony Haden-Guest, the bibulous English socialite and journalist satirized by 'Tom Wolfe' in The Bonfire of the Vanities (1990).
Guest became the 5th Baron Haden-Guest, of Saling in the County of Essex, when his father died in 1996.
Attended the House of Lords regularly until the passage of the House of Lords Act 1999 barred most hereditary peers from their seats.
He has been a skilled guitarist since the 1960s and has displayed his talents in both Spinal Tap projects and A Mighty Wind (2003). He actually became acquainted with frequent co-stars and on-screen band mates Michael McKean and Harry Shearer at music venues before the three decided to make a career as comedic actors.
Was the muse for an Asian-American short comedic film entitled Pax Importi Modellus: The Rise of the Import Model (2004), which has gained international attention.
In 2005, announced his intention to stop making mockumentary films, because he doesn't find them funny anymore.