They've had playdates before in Los Angeles.
So, it was natural for Angelina Jolie and Gwen Stefani to get their children together when they coincided on this side of the Atlantic.
The Hollywood supermum dropped in on Gwen's London home with four of her six children.
Gwen divides her time between California and the Primrose Hill district of the capital because her husband Gavin Rossdale is British.
Their five-year-old Kingston has his birthday the day before Angelina's little girl Shiloh in May.
And, the actress' twins, Vivienne and Knox, are the same age as Kingston's brother Zuma, three.
The youngsters looked like they had a ball together, with several of them sporting face paint on leaving.
Glam globetrotter Angelina has become a dab hand at keeping her lively bunch entertained on the go.
She's been pictured popping into an arts and crafts shop in Richmond and on trips to the London Aquarium and the theatre.
The Jolie-Pitt clan is in Britain while dad Brad films a zombie thriller.
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