Gwen Stefani and her son Kingston

Brad Pitt and Angelina Jolie have been making the most of being back on home territory with an invitation to family friends Gwen Stefani and Gavin Rossdale to pop over for Sunday afternoon.

Gwen Stefani

Brad shows his adopted son how quad biking's done.

Two of Hollywood's most celebrated babies - Kingston Rossdale and Shiloh Nouvel Jolie-Pitt - came together, along with their famous parents, for a baby playdate on Sunday.

Gavin Rossdale and Gwen Stefani joined Angelina Jolie and Brad Pitt at the couple's Santa Barbara, California retreat during the long fourth of July holiday weekend.

The new mums were seen sporting matching baby slings and chatting, meanwhile, Pitt and Rossdale enjoyed a bit of jet skiing.

Jolie and Pitt's son Maddox was seen hanging out with the boys, while the couple's 18-month old daughter Zahara, was spotted toddling about enjoying the sun.

Security at the luxury compound was on high alert and the estate was heavily guarded by officers on dune buggies, patrol boats and rafts, as well as dogs posted around the properties perimeter.