Jennifer Lopez felt she had "graduated" as a singer when she performed at husband Marc Anthony's 40th birthday party.

The 'Love Don't Cost A Thing' hitmaker admits she was nervous about dedicating Barbra Streisand song 'My Man' to Marc but knew she needed to do it to prove her credentials.

She said: "I sang a song for Marc's birthday, for his 40th birthday, called 'My Man,' which is an old Barbra Streisand song from 'Funny Girl'. When I sang it, you know, she's so my idol. I was like, 'I cannot believe I am trying to sing a Barbra Streisand song, this is insane! What are you thinking?!' But I sang and it was almost like I had graduated, you know what I mean? But I needed to get to that point.

"I sang and he was like, you know the tears in his eyes. And we were both like, 'What was that?' I was like, finally, I am a singer. This is what I do. I don't ever have to doubt that in my mind, nobody can ever make me doubt it again."

Jennifer also revealed she plans to take her 22-month-old twins, Max and Emme, with her when she tours next year.

She told US TV show 'Access Hollywood': "They are going to have to go with me. Sometimes we have them in studio, sometimes I'm just like, 'Let me go in really quick and get back home really quick, but it's always with them in mind.

"For anybody who has children, you know, your priorities change as a mom. You just have to... always work everything around their happiness... and their well being."