Who could say "No" to Jim Carrey? The A-list funnyman plays a down-on-his-luck guy who is transformed by the simple power of "Yes" in his new comedy 'Yes Man,' in theaters Friday -- Jim's long-time girlfriend Jenny McCarthy was at the premiere and she opened up to ET about her romance with the star of the night.

ET's Thea Andrews spoke with Jenny on the red carpet, and the blonde beauty opened up about her relationship with Jim and why the couple is happy simply being together without tying the knot.

"We both know that we both do not want to get married, and that doesn't mean that there's a part of us that doesn't love each other," Jenny says. "To us it's a little bit more romantic that we don't want to tie the knot, because we're together strictly because we want to be and not because someone has a certificate that says so. I love the fact that I want to just eat him up without him being my husband."

Also starring Zooey Deschanel, Bradley Cooper, Danny Masterson and Terence Stamp, 'Yes Man' finds Jim as a guy whose operative word is "No" -- and his life is going nowhere. But when he reluctantly signs up for a self-help program, the power of saying "Yes" to everything soon transforms his life in amazing and unexpected ways. But is his willingness to embrace every opportunity too much of a good thing?

Watch ET for more with Jim!