Gwyneth Paltrow is a "nervous wreck" when she has to sing in public.

The 'Country Strong' actress has showcased her vocal talents at a number of high-profile events this year but she still gets scared when she performs, and 'Glee' star Matthew Morrison says she was equally terrified when they recorded a track for his self-titled debut album together.

He said: "She was nervous. She's such a good singer and she gets nervous to sing, which is funny because she sang at everything this year - the Grammys The Oscars - and she was such a nervous wreck every time she had to go out there, but she was amazing every single time.

"She didn't really know the song; obviously she knew 'Somewhere Over the Rainbow,' but she didn't know that version so I taught it to her in the studio and she picked it up really fast because she's got a great ear."

As well as collaborating with Gwyneth, Matthew's album also features a duet with Sir Elton John and the actor was terrified of asking the musical legend to work with him - and incredibly surprised when he said yes straight away.

He recalled to AOL: "That one was tricky because I don't really know him that well; I didn't back then. I went to his Oscar party and then he invited me to this White Tie and Tiara Ball in London that he has every year, and then I found out he was a 'Glee' fan.

"My hands were sweating and I walked up to him and was like, 'Hey, Elton how's it going?' He's a lovely guy, and I said, 'I'm doing this album and I would really like to sing with you on it if you would do that for me,' and he was like 'yeah, absolutely!' I was like, '"Oh, man that was just so easy.'

"It was one of those things where, three days after we recorded it, it finally sunk in and I was like, 'Oh my God, I just did a duet with Elton John.' It was very surreal."