Gwen Stefani and Gavin Rossdale reunite for son's ball game

Gwen Stefani put on a united front with ex-husband Gavin Rossdale on Wednesday (18May16) to cheer on their eldest son during a basketball game.

The No Doubt frontwoman split from her husband of 13 years last August (15), amid allegations of his infidelity, and they finalised their divorce in April (16).

Gwen was photographed looking stone-faced and agitated as she drove away from a meeting with her ex in Beverly Hills, California last week (12May16), and on Wednesday, the pair reunited once more to support nine-year-old son Kingston as he took part in a basketball game.

But, while Bush rocker Gavin was caught on camera smiling, it was clear the blonde beauty was unable to relax and enjoy the action in her ex's presence, as she stood stiffly nearby.

The sports outing marked the first time Gwen and Gavin had been snapped together since their break-up.

The musicians are also parents to sons seven-year-old Zuma and two-year-old Apollo.

After her split from Rossdale, Gwen moved on to date fellow singer Blake Shelton, who she worked alongside as a judge on U.S. talent show The Voice, and the pair has been gushing about the romance for months.

The country star opened up about their unlikely romance during an interview on U.S. breakfast show Today on Thursday (19May16), admitting, "We could not be, on paper, any more different. I'm a country singer and she's a ska, rock, pop, whatever it is... It's just an odd idea. But man, it's a lot of fun."

Blake was also newly-single when his friendship with Gwen turned romantic after divorcing his wife Miranda Lambert in July (15).