Russell Brand is a ''devoted father'', according to his fiancée's sister.

The 42-year-old comedian has six-month-old daughter Mabel with his partner Lauren Gallacher, and despite her older sister Kirsty describing the funny man as ''wonderful'', she has been left shocked by the ''embarrassing'' X-rated jokes he tells audiences about his sex life.

When told about the contents of his stand-up material by The Sun newspaper, Kirsty said: ''Oh my days. I haven't quite got myself in the zone to go and see one of his shows. I do need to but I will be so embarrassed at those bits. I can't believe he talks about her like that. I've heard he describes little Mabel as 'the sperm who made it'. But he is wonderful, and it's all very tongue-in-cheek. He's such a devoted father, it's very lovely to see.''

Meanwhile, Russell - who was formerly married to pop megastar Katy Perry - revealed earlier this year that he and Lauren intend to let their daughter ''formulate'' her own gender identity and won't dress her in feminine clothes.

He said: ''Now that I have these very important women in my life, I have re-evaluated the way I look at gender. I don't have to dress her in feminine clothes, I don't need to dress her in clothes for her gender, I'd rather just see how she formulates it herself. I've become quite sensitive and aware of that since she was born.''

Russell also revealed that he is a hands-on father but admitted that his life has changed dramatically since Mabel was born.

He said: ''It's an abrupt and sudden change. It's like having a relative over to stay, but not a minor relative, like a distant uncle. There's not an area of her life I'm not involved in. Sadly I'm unable to produce breast milk.''