Mariah Carey's twins are to make their recording debut on their mother's next album. The singer is mum to two-year-old Moroccan and Monroe, with her husband Nick Cannon, and she has revealed the youngsters will be featured in a new song after she recorded their parts on her cell phone. She tells People.com, "It's a song that I wrote with (songwriter) Bryan-Michael Cox and (producer) Jermaine Dupri. There's a part that Jermaine says on the song that (the kids) loved, and Monroe started to say it. I kept having to get my iPhone and record her. So I have all these different takes of her saying things, singing things. Then I'd be like, 'This is your new ad lib - learn it!' I have to make it fun for her." Carey's new record, The Art of Letting Go, is due for release in May (14).