Nicole Kidman and Keith Urban's daughters love singing.

The couple have two children, Sunday Rose, five, and Faith Margaret, two, and the 'American Idol' judge, 45, believes they might follow in his footsteps.

The country music star told People magazine: ''Sometimes I'll just hear Sunny singing 'Kiss a Girl. It's just infectiously catchy pop and I have a side of me that loves that stuff.

''She sings 'I Love It' by Icona Pop all the time. She and Faith sit in back of the car and sing, 'I don't care, I love it, I love it.' We've had to figure out the clean version of the song.''

The girls also sometimes make up their own songs, much to the delight of their parents.

Keith, who has been married to Nicole for seven years, said: ''They'll just mishear the lyrics. Sunny used to sing [Foster the People's] 'Pumped Up Kicks' and she thought the lyric 'faster than my bullet' was 'faster than my brother' and so that's what she sang. It's adorable.''

Oscar-winner Nicole, who recorded a version of 'Somethin' Stupid' with Robbie Williams and the duet became a number one hit in 2001 in the UK, previously admitted she would love if Sunday became a professional singer.

She said: ''She has really good pitch. I'd love it [if she sings]. The great thing about being married to a musician is you have music in the house all the time. [Keith will] play the piano at 7 a.m. ... We have breakfast around the piano.''