Juliette Lewis “Brown Bikini” with red flowers during a Mexican holiday

It's hard to believe Juliette Lewis is almost 40.

The Firm actress showed off her fabulous figure in a brown bikini decorated with big red flowers during a holiday in Mexico.

As usual, the Natural Born Killers star let her long brown hair go with the flow.

Birthday babe: Actress Juliette Lewis went to a Mexican resort to celebrate her 39th birthday (Read more and See more Pictures)