Yummy mummy club: Christina Aguilera marks Max's birthday with Gwen and her son

Christina cuddles the birthday boy while they take a ride in a fire truck with Gwen Stefani, her eldest son Kingston and Sesame Street favourite Elmo
 Photo: © Rex

With presenting duties at this year's Golden Globes and her son's second birthday to celebrate, mum-of-one Christina Aguilera had her hands full this weekend.

The day before the annual ceremony, the Burlesque actress and her little boy boarded a Seagraves fire-fighter's truck for a ride along with a very familiar face, Elmo.

And if the sight of Sesame Street's beloved furry red muppet didn't make the birthday boy's day, Max and his mum, 29, were also joined by another famous mother and son team.

Gwen Stefani and her elder boy Kingston, three, were also riding the vehicle as it trundled along the streets of Beverly Hills.

The encounter gave yummy mummies Gwen and Christina the chance to catch up – the pair have forged a friendship since becoming mothers, attending baby showers and birthdays with their children.

Saturday's excursion followed another play date for 40-year-old Gwen, who spent Friday with her husband Gavin Rossdale and their two sons at a park in LA.

The singer and her musician husband played around in the sand with Kingston's little brother Zuma, who is one, before the blonde beauty headed off to keep a watchful eye on her first-born.