Joining the previously announced Tamzin Outhwaite are Robert Webb, Sarah Hadland, Ifan Huw Dafydd, Barnaby Kay, Bel Powley, Issy van Randwyck and Nicholas Rowe.

The play is directed by Hampstead's artistic director, Edward Hall, designed by Jonathan Fensom with lighting by Rick Fisher, sound by Matt Mackenzie and music composed by Simon Slater.

In the play, which is described as a study of modern parenting and matrimonial tribulations, "Briony and Keith are not finding parenthood easy so their friends, the delightful Ross and Rosy, engineer a relaxing weekend away in Wales: intelligent adult company, good food and drink, complete rest – and absolutely no children. But they make up the numbers by inviting the unpredictable Charles and Serena. Add an uninvited anarchic adolescent and fanatical farmer and Briony and Keith's idyllic weekend erupts into total chaos."

Outhwaite was last seen at Hampstead Theatre in Di and Viv and Rose, and other recent West End credits include Sweet Charity (transferred from the Menier Chocolate Factory) and Boeing Boeing.

Webb is best known for his comedy work as a television comedy writer and actor, including eight series of "Peep Show," "That Mitchell and Webb Look," "Fresh Meat" and "Threesome." Stage appearances include Mitchell and Webb productions and Neil LaBute's Fat Pig in the West End. Films include "The Wedding Video," "Magicians" and "Confetti." He has written and performed extensively for BBC Radio. Hadland is well known on TV, having previously worked with Robert Webb on three "Mitchell and Webb" series, and in "Burton And Taylor," "The Job Lot," all three series of "Miranda" and two series of "Waterloo Road." Stage appearances include Canvas (Chichester Festival Theatre), Decor Without Production (Royal Court) and The Vegemite Tales (Riverside Studios). Films include "Royal Wedding," "Leap Year" and "Quantum Of Solace."

Dafydd has worked extensively with Clwyd Theatr Cymru. Film credits include "Martha," "Jac A Sianco"(BAFTA Best Actor 2009), "Abraham's Point" and "Daddy's Girl."

Kay's stage appearances include Danton's Death (National), The Real Thing (Old Vic), A Streetcar Named Desire (Donmar Warehouse) and War And Peace (Shared Experience).

Powley was recently seen in the West End in Jumpy (transferred from the Royal Court to the Duke of York’s). She has appeared on Broadway in Arcadia.

Van Randwyck's many stage appearances include The American Clock (Finborough), No Naughty Bits (Hampstead), Marilyn Monroe in Becoming Marilyn (Riverside Studios/Assembly Rooms) and A Little Night Music and Once in a Lifetime (both at the National). She has also appeared frequently at Chichester Festival Theatre.

Rowe's previous stage appearances include The Madness Of George III (Bath Theatre Royal & Tour), Nation (National Theatre Studio), Victory (Arcola), and Whipping It Up (Bush).

To book tickets, contact the box office on 020 7722 9301, or visit www.hampsteadtheatre.com for more details.