Megan Fox stunned at the premiere of "This Is 40" last night in Hollywood -- and she's made a major transformation during her 11 years in the biz.

In that short time, the 26-year-old has gone from a "7th Heaven" star's arm candy to "Transformers" sexpot to married mom while also playing with her look.

And it's been a fun ride to watch, hasn't it?

The gorgeous gal has changed her personal style a lot through the years ... and there have been some major fashion and beauty hits and misses.

Click here to see the photo gallery! WOW