Amanda Seyfried has revealed that she signed onto Ted 2 "blindly".
The Les Miserables star admitted she agreed to star in the comedy sequel after working with Seth MacFarlane on his A Million Ways To Die In The West, despite not knowing anything about her character or the plot.
"I signed on blindly because I trust him. He said, 'Will you do this for me?' and I said yes. How can anybody say no?" she said.
"I have no idea what I'm doing. I literally don't know. And we're shooting in two months," she continued, adding: "I know what I'm wearing."
Amanda, who has sang in Mamma Mia! and Les Miserables, will have to tune up her vocal cords once again for Ted 2, which will star Seth as the voice of the foul-mouthed teddy bear and Mark Wahlberg as his owner and friend John Bennett.
"Seth's an amazing singer. I'm not as good. He thinks I am so he wrote me a song to sing in Ted 2, which will be interesting," she said.
Amanda also revealed that the pair have built up a good working relationship, after collaborating together.
"Seth is definitely a good friend to me. I think we are good together. We both have a good banter back and forth," the 28-year-old said. "He makes me feel smarter than I probably am and I think that's a nice treat to have as a friend."
:: A Million Ways To Die In The West is in cinemas now. Ted 2 will be released in 2015.