I hope everyone enjoyed the Academy Awards last week—I know I did.

If nothing else, the Oscars signal that spring is just around the corner. For me, it’s also an opportunity to guess which stars had work done since I last saw them.

Of course the biggest cosmetic surgery headlines of last year belonged to Renée Zellweger, who made news by emerging as a version of herself that many people thought looked…well, nothing like herself.

It’s unclear whether Ms. Zellweger had cosmetic surgery or not. And if she’s happy, I’m happy—it was the reaction to her new appearance that really resonated with me.

Naturally, I thought about business and branding! I can’t help it.

Companies re-brand all the time, and that’s a good thing. Organizations age, styles change, and cultural expectations evolve.

We tend to like it when our favorite brands take a hard look in the mirror, recognize that there are opportunities to improve their product and image, and take action—as long as they continue to remind us why we loved them in the first place.

That brings us back to Renée Zellweger. Plenty of Hollywood stars have had work done. Usually, they look a little younger, or thinner, or perkier, etc.

In Ms. Zellweger’s case, however, the Internet ruled that she had changed the essence of her brand. Her formerly hooded eyelids, which helped make her endearing and relatable to so many, were suddenly gone. Some felt like they didn’t know her any more.

Branding is an interesting thing. Coke can change their tagline every five years—if it still stands for happiness. And McDonalds can start offering healthy alternatives to the Big Mac—as long as they don’t get rid of the golden arches.

So, brand managers and Hollywood stars, take note: A nip here, a tuck there…no problem. But don’t change who you are.

—Richard J. Lenz