Kat Dennings thinks Kim Kardashian's butt is "amazing."

The 28-year-old star told 'The Ellen DeGeneres Show': "I didn't know what to expect because she's so famous. I was very nervous because I've seen so many episodes [of 'Keeping Up with the Kardashians'], and she was very sweet. She was very nice. And her a** is amazing! I am feminism, girl power, but I was just so in love with her a**. I just spit talking about it - that's how passionate I feel!"

She added: "She's gorgeous. It's just amazing. I've never seen an a** like that in my life. There's an episode of 'Keeping Up With the Kardashians' - an oldie, a vintage one, before she and [Kanye West] got married - and she was doing her music video and Kanye was there and he was like, 'I have never seen an a** like that.' And that's what I was thinking!"

Kat recently started dating Josh Groban after her co-star Beth Behrs introduced her to the singer, 33, and thinks he's a "wonderful person."

She said: "He's very witty on the Twitter and I saw his little tweets...and sometimes we would [tweet back and forth]. But, yeah she's always talked about how great he is. They've been friends for years. And she thought we were both, you know, nerds. So there, she was right."