Begin Again stars explain just how difficult it was to act and sing in the movie.

In an interview with the The Hollywood Reporter, Adam Levine and Keira Knightley of Begin Again, Explain just how difficult it was to both act and sing in the movie:

"I think I just blocked it out of my head until I actually got into the studio and then went, 'Oh f---, I have no idea how to do this,' Knightley said of singing in the movie. "And I was very fortunate because there were some lovely people who held my hand, and we just worked it and worked it until we found something that was all right."

The most difficult thing that Adam Levine found about the movie was actually the acting itself:

"I literally had to pretend that I knew what I was doing, in pretending to be another person," he explained. He also said that it was "very meta."

According to The New york daily News, the two stars admitted that they felt out of their comfort zones, both trying out what the other usually does professionally:

"I kept telling her she was great and she wouldn't believe me, and she told me that I wasn't bad at acting either but I didn't believe her, so it was perfect," Levine said Saturday Tribeca Film Festival.

Read more: http://www.nydailynews.com/entertainment/movies/adam-levine-acting-debut-keira-knightley-sings-article-1.1770688#ixzz308RzF0e1

Begin Again stars Mark Rufallo, who was the star of Now you see me, as well as Hailee Steinfeld, Catherine Keener, and CeeLo Green who has a cameo role. The movie plans on opening in July.