Teri Hatcher shows off her "bob." Photo: Peter Brooker, Rex USA

Mum's the word!

Though she's been steaming up our TV screens in skimpy lingerie on "Desperate Housewives," Teri Hatcher has opted for a more conservative makeover off the set.

Swell.

The 45-year-old actress -- who recently discussed aging with Oprah Winfrey -- has traded in her long dark locks for a poufy mom bob -- sort of.

Hatcher debuted the full, layered look at the Global Creative Forum Evening of Entertainment in Beverly Hills, where she also rocked a prim and proper gray dress with a high collar.

But fear not, folks. Thankfully the helmet hair -- which referenced Hatcher's "Lois & Clark" bob -- was only temporary, as the star had her still-intact long tresses swept back into a bun, according to the Daily Mail.

Phew.

It wouldn't be the first time Hatcher has fooled us with a faux bob, but hopefully it's the last. We no likey.

In other hair news, Brazilian Blowout hair-straightening treatments are causing plenty of controversy.

And click here for the top 8 celebrity bobs.