Kate Middleton joined her husband, Prince William, and their three children for a church service, where she debuted her blonde hair.

Kate tends to keep a low profile. The last time we saw her was at Wimbledon in mid-July, when she was still rocking her signature brunette with just a hint of caramel. Fast-forward a few weeks, and she's several shades lighter, showing off a sun-kissed blond that feels perfectly timed for late summer.

Kate Middleton's hair is lighter than ever, just in time for back-to-school season. But the mom of three has a tendency to switch it up when change is afoot.