Under the Influence Review at King’s Head Theatre London

Written by identical twins Carine and Frances Gilbert, Under The Influence is a new musical comedy that explores the wonderfully complicated relationship between two sisters. After becoming a viral sensation, the twins find themselves in couples therapy as the world’s most co-dependent non-couple, where the session quickly descends into a hilarious musical intervention and a reckoning that threatens to disrupt their lifelong duet. The twins return to their musical theatre roots with an original score composed by Shona Maule and directed by Georgie Rankcom. Following award wins at the Fringe Theatre Awards and Edinburgh Independent Awards, Under The Influence has now arrived in London for a limited season at the King’s Head Theatre.

With more than 3 million followers and 210 million views each year, @thegilberttwins are certainly no strangers to sharing their lives with the world. Although online fans have already been given a front-row seat to so much, Under The Influence brings something different to the relationship we think we know, using music, humour and genuine warmth to explore what lies beneath the surface. Despite their enormous online following, the show feels surprisingly fresh, intimate and, ultimately, rather heartwarming.

Both Carine and Frances put their Guildford School of Acting training to excellent use, performing with dexterity, compassion and vulnerability. There is a real sense that we get to know the individuals behind the online personas, with the audience given a glimpse into each twin’s personality, hopes and dreams.

Shona Maule’s score is musical-theatre pop at its finest, with memorable melodies and lyrics. It is not often that a new musical feels genuinely fresh, particularly when so many productions can feel heavily influenced by what has come before, but Maule’s score scratches that particular itch with a solid, polished and musically assured score. Georgie Rankcom’s expert direction keeps the momentum moving while allowing the emotional stakes to develop naturally, ensuring the comedy and more heartfelt moments remain well balanced. Together, the performances, score and direction combine to create a little gem of a show that should leave both existing Gilbert Twins fans and newcomers thoroughly entertained.

Whether you are already one of the millions of people who follow The Gilbert Twins online or are discovering Carine and Frances for the first time, Under The Influence is well worth your time. Funny, heartfelt and packed with infectious tunes, it offers an entertaining glimpse into the unique bond between two sisters while reminding us that even the relationships we think we know can still surprise us.

With plenty of laughs, moments of genuine warmth and a score that will have you humming on the way home, this is a little gem that deserves to find its audience. Catch it at the King’s Head Theatre while you can.

Under the Influence plays at King’s Head Theatre until 26 September 2026.

Where I Sat

Seating for Under The Influence is unreserved, but with the audience seated on three sides of the stage, there really isn’t a bad seat in the house, with adequate leg room and a clear view of the stage. The theatre itself is located in the basement, around four flights of stairs below street level, although a lift is also available. In fact, each step is marked with the name and year of a previous production, giving you a little glimpse into the theatre’s history as you make your way back to street level after the show.

Reviewed by Stuart James for SeatPlan, September 2026