Kate Middleton Flaunts New Blonde Hair in Public for First Time

Summer may be coming to a close, but Kate Middleton is fully embracing her sunny new 'do ... putting her blonde locks on display for the first time in public.

Check it out ... the Princess of Wales stepped out alongside her husband, Prince William, on Thursday to pay a visit to London's Natural History Museum ... where they took in the museum's new and improved gardens.

However, it wasn't the flowers that had everyone clamoring, as the princess emerged with honey blonde highlights ... a striking difference from her usual dark 'do.

She wore the blonde strands down in loose curls, which rounded out her business-casual fit of a brown blazer, dark slacks, and a white button-down.

Kate's massive sapphire wedding ring -- an heirloom from the late Princess Diana -- even took a back seat to the blonde hair ... so, you know it's a big style shake-up!!!

Fans of the royal first caught a glimpse of her big makeover last week, when Kate was seen rocking the lighter hair color while out and about in Scotland with her family ... including sons Prince George, 12 and Prince Louis, 7, and daughter, Princess Charlotte, 10.

Yet, it wasn't until today that Kate gave the people an up-close look at her new look.