Peter duBois, who directed the play's original Off-Broadway production at Second Stage, will helm the London production as well.
Myles, who has also appeared in TV's "Doctor Who," "Belonging," "Merlin" and "EastEnders," commented in a statement, "I'm delighted to have been cast as the character of Emma in such a well anticipated and funny play. Having concentrated on TV work recently I'm excited to be returning to the stage and I'm very much looking forward to working with Zach and Peter."
Fielding, whose TV roles include appearances in "Wallander," "Doctor Who" and "Pete Versus Life," added, "I am very excited to be appearing on the West End stage in All New People. With such a witty script and some fabulous lines, I am really looking forward to getting my teeth into playing the role of Kim."
Prior to the West End, the play will try-out in Manchester from Feb. 8-11 and Glasgow from Feb. 14-18.
Set in the dead of winter, the play revolves around Charlie (Braff) who, at his wealthy friends’ luxury Long Beach Island apartment, has hit rock bottom on his 35th birthday. Away from the rest of the world, this perfect escape is interrupted by a motley parade of misfits who show up and change his plans. A hired beauty, a fireman, and an eccentric British real estate agent desperately trying to stay in the country all suddenly find themselves tangled together in a beach house where the mood is anything but sunny, while Charlie just wishes they'd leave and let him get on with it.
To book tickets for the West End run, contact the box office on 0844 871 7623, or visit www.allnewpeople.co.uk for more details.