Scarlett Johansson has won rave reviews for her starring role as a voice - the computer voice with which Joaquin Phoenix falls in love - and only a voice in the critically acclaimed Spike Jonze film "Her."

It's a strange place for the actress to find herself considering she couldn't get a commercial job, she says, as a child actress because of her voice.

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That makes it all the stranger that Johansson, 29, will be starring in the Super Bowl of commercials, literally, when this year's Super Bowl XLVIII kicks off Feb. 2.

"It's funny," Johansson told ABC News' Bianna Golodryga of being hired by SodaStream International Ltd., as the first-ever Global Brand Ambassador for its home soda-brewing system and kicking it off with a Super Bowl commercial.

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"I could never book anything because of my voice as a kid, as far as commercials went, because I just didn't have that real bubbly and, you know, that little kid voice that sells products and toys and all that stuff," Johansson said.

Also adding to the irony of her own Super Bowl commercial is that Johansson, a Broadway actress in addition to a Hollywood movie star, admits that she just recently started paying attention to football.

"I haven't understood the rules of football up until a couple of years ago when finally somebody sat me down [and] they were like, 'OK, we're going to explain this to you,'" she said. "Because I just thought, 'Why are they all running? They're all running after it at the same time. There's no rules.'"

Johansson has a good excuse for her lack of American football knowledge, considering that she has been spending a lot of her time in France, the home country of her new fiancé, journalist Romain Dauriac.

They became engaged last summer, but Johansson says that doesn't mean she's going to be walking down the aisle anytime soon.

"I'm not doing any wedding planning," she said. "That's far off my mind right now."

Johansson and Dauriac were first reported to be dating in late 2012.