Jennifer Garner "cried" when she duetted with Andrea Bocelli.
The Hollywood actress sang alongside the classical singer on the track 'Dormi Dormi Lullaby' for a special edition of his album 'Si Forever: The Diamond Edition' and admits she balled her eyes out as she was feeling "so incredibly nervous".
Speaking on The Ellen DeGeneres Show, she said: "Is that the craziest thing? If you just said list the 10 craziest things that have happened in your life, that would be on there. I think they had recorded this beautiful lullaby and they wanted a more of a mom person who was less of a singer singer, so they came to me, but then it turns out I had to really sing sing, so I had months of lessons. I was so incredibly nervous: I cried in the parking lot, I cried while I was recording it.
"I had to keep my eyes covered to deal with the fact that I was even recording it! Mr. Bocelli wasn't there, but he was in my ears in cans you know and so I could hear his voice and it just is so magnificent it just kind of left me up and I did it."
Other stars to sing on the album include Ellie Goulding.
She said: "I have always had an affinity with classical music, and I'm a sucker for a love song. It was fun and enlightening to sing in Italian - a real joy to record."
Andrea added: "Ellie Goulding is the perfect singer for this track. "She has a beautiful voice which I loved right away."
Andrea also worked with stars including Ed Sheeran and Dua Lipa on the original version of the album and he was delighted with the chance to team up with them both.
He said: "I loved Dua's voice - it's very recognisable and has a lot of tension. With Ed, he has a great determination and lots to communicate, and he does that in a sincere way. He's a great guy."