Underwood hits the high notes at a country music festival in London. Plus: Zac Efron, the Garner-Afflecks, Fergie & Josh Duhamel and more

GOOD TO GO

Heidi Klum gears up for her self-proclaimed workout of choice – keeping up with her kids! – Sunday on a Brentwood, Calif., stroll with 7-year-old Henry and 3-year-old Lou, plus beau Martin Kirsten.