The 'Celebration' singer – whose eight-year marriage to movie director Guy Ritchie ended in December – has dispelled rumours she is planning to wed her 22-year-old boyfriend Jesus Luz and claims marriage is the last thing on her mind.

When US talk show host David Letterman asked about possible future nuptials, she replied: 'I think I'd rather get run over by a train."

However the 51-year-old star – who has daughter Lourdes, 12, son Rocco, nine, and adopted children, David and Mercy, both four - admitted there are some aspects of married life she misses.

She said: 'Being a single parent means you're kind of in charge of everything. You can't say, 'Hey, can you give the kids a bath while I do something else.' There's no job sharing.'

The pop star – who was previously married to actor Sean Penn – also revealed she looked like a 'fool' when she appeared on David's show in the 90s because she had smoked a 'joint', a slang term commonly used for a cannabis-laced cigarette, before the interview.

She said: 'I think I may have made a fool of myself once or twice on your show. But it wasn't that I was excited about you. I think it may have had something to do with the joint I smoked before I came on. But I didn't inhale, so it doesn't count really!'