Kirstie Alley: Scrutiny over Lady Gaga's Weight Is 'Insanity'

Lady Gaga isn't the first celebrity to put on a few pounds.

If anyone can relate to being scrutinized for weight gain, it's Kirstie Alley.

"Most of my career I was pretty lean, so when I gained the weight, obviously people [noticed]," the former Fat Actress star, 61, tells PEOPLE. "With [Lady Gaga], she gains [25] pounds and it becomes this huge thing."

Gaga, 26, who acknowledged her weight gain to radio host Elvis Duran last month, recently posted a quote on her website from Marilyn Monroe that said, "To all the girls that think you're ugly because you're not a size 0, you're the beautiful one. It's society who's ugly."

Alley agrees with that sentiment, saying, "It's Hollywood that is obsessed with weight. I think everyone should try to be healthy. Lean is better than not lean, but I think we send a horrible message to the world, especially to girls."

As for the amount Gaga has gained, the Dancing with the Stars all-stars contestant says, "She was so freaking skinny that [25] pounds would make her a what, size 2? There's an insanity here. I know it's a pressure on her. I know it is. It's really hard to play that game."