Gwen Stefani nail salon Santa Monica

After giving birth to three boys, Gwen Stefani can at least take a break to get her nails done, right?!

The devoted mom and uber-cool pop star hit up the nail salon solo, on Thursday ... I mean, with FOUR boys in the house (including Gavin), who wouldn't want a little peace and quite on a 100-degree afternoon?

The workaholic recently signed on as a judge on the upcoming season of The Voice, as a pregnant Christina Aguilera takes maternity leave. But there's no rest for the weary -- Gwen gave birth just two and a half months ago and she's already signing contracts, y'all. Talk about a working mom!