SAOIRSE Ronan is growing up fast.
We had got used to seeing her playing feisty tomboys but the 18-year-old proves she's all woman in upcoming film The Host.
Saoirse (18) gets up close and personal with her hunky co-star Max Irons -- the actor son of Jeremy Irons and Sinead Cusack -- in a steamy love scene which marks her first major on-screen kiss.
In the new trailer, the two lock lips in the pouring rain in the middle of the desert.
The film is your classic love story; guy meets girl, sparks fly, and they fall for each.
Then, her body is invaded by futuristic aliens and things start to fall apart.
The film is the latest offering from Twilight author Stephenie Meyer.
Breaking Dawn: Part Two hit cinemas earlier this month and marked the beginning of the end for Meyer's vampire saga, but it looks like she may already has another blockbuster on her hands.
And Saoirse is a big fan of Stephenie's work. "Twilight kind of took over the world there for a while so I was very familiar with Stephenie's books," she said.
"I read the script for The Host and I just thought the idea was so incredible."
Set in the future, the film is about a group of mind-invading aliens who plan on taking over the human race.
Saoirse plays the parts of both Resistance fighter Melanie Stryder and blue-eyed alien Wanda, which she says was a fantastic experience.
"They are two separate young women, and they're very different. Melanie is a lot tougher than alien Wanda," she said.
"Playing two characters in one film; that's always an actor's dream."