Five months ago "American Idol"'s favorite sushi neophyte Kellie Pickler was a red-blooded  meat-lovin' American gal. But now the "Red High Heel" lovin' singer tells People magazine that she has joined her veggie-lovin' country superstar friend Carrie Underwood in becoming a vegetarian!

When Pickler first told Underwood about her switch from steak to sprouts, the "American Idol" winner was a bit disbelieving, "I texted Carrie and was like, 'You're never going to believe this!' And she was like, 'No way! I'll give you three days!'"

But five months, later Pickler is still going strong and since then Underwood -- a long time vegetarian -- has been schooling Pickler in the ways of a meat-free lifestyle.

"We have this little vegetarian thing going on. I'll text [Carrie] and be like, 'Is fish considered a meat?' And she'll be like, 'Well, different people look at it differently.'"

Pickler also said that at first she chose her meat-free lifestyle for health reasons, but was also persuaded by a PETA (People for the Ethical Treatment of Animals) ad she saw on TV featuring Pam Anderson to do some more research on animal cruelty. "I saw all the videos and I just thought it was horrible. It's animal cruelty. A lot of it has to do with knowing what happens to the animals and it really bothered me and so I will not eat meat."

Kellie also tells the mag that her friend and new diet mentor has done nothing but encourage and support her since the change. "[Carrie] was like, 'Wow, I'm so proud of you! You're doing better than I thought.'"