Carrie Underwood is sick of birthday compliments.

The former 'American Idol' winner hit 30 on March 10 and ever since all people have done is told her how great she looks for someone of her age.

In an 'On Air with Ryan Seacrest' interview, she moaned: ''It's just been absolutely amazing to me how many people have been like, 'Oh happy 30th birthday. Oh yeah, 30, but you look great.''

The blonde bombshell can't understand the motivation behind the compliments, adding: ''Was I, like, supposed to start falling apart? Like, transformation into old lady-hood was supposed to be complete by 30? I'm not sure what that means!''

Perhaps the reason why Carrie looks so good is because of her vegetarian diet.

The country singer became a vegetarian at the age of 13 and she finds it easy living a meat-free diet, even though her husband, ice hockey player Mike Fisher, is a committed carnivore.

She previously said: ''I am 100 per cent vegetarian but I try my best to be vegan. It's getting better. There are so many restaurants that will work with you - even steakhouses. My husband loves to eat meat and there's a place called King Prime that we like to go to. They're always really nice to me and give me veggies if I ask for them.''