Martha Wainwright, gig review: It was a happy, family affair as the singer's young son sang along

At the London Southbank Centre the latest Wainwright family talent, Arc aged 5, took to the stage alongside his mother

A small man in a kilt stole the show at Martha Wainwright's London gig. Aged five, Arc joined his mother on stage for a series of songs, during which he crawled under the piano, impersonated his mother using a cup and bottle as his mic and dramatically leaning on the amp.

There was still the melancholic material of old including "Far Away", "This Life" and "Bleeding All Over You", but she was accompanied by her young son, husband and cousin - the latter two of whom offered backing on the piano and vocals. Her new work focuses on motherhood and marriage, which was playful and witty, rather than sentimental.

Wainwright's voice is still her ultimate instrument; she accompanied herself on the guitar, but it is her voice that beguiles. It's unequivocally powerful without being melodramatic, switching pitches with ease, and with unique attitude.

Next year will mark the tenth anniversary of Wainwright's first record and she seems more comfortable on stage that ever. Instead of some of the covers originally by her musician parents, fans may have appreciated more from her well-loved first two albums.

However, it was almost an Audience With Martha Wainwright in terms of intimacy and interaction. Happiness, it seems, quite becomes her.