Gwyneth Paltrow is a huge fan and wants a role in the fourth series of the period drama, which is to air later this year.

A source told America's Star magazine: “Gwen just wrapper 'Iron Man 3' and is so sick of blockbusters and wants to focus more on TV.

“She adored working on 'Glee' and told her team to get her on to 'Downton Abbey'. She's been told that creator Julian Fellowes is thrilled and is fleshing out a cameo for her.”

While Julian refused to give away many details for the fourth season he has revealed there will be tough times ahead for Lady Mary Crawley following the death of husband Matthew Crawley in the Christmas special.

He said: "There are tough times for Lady Mary I think we can say that."

He also explained he is keen to see Shirley MacLaine reprise her role as Martha Levinson, the US mother of Lady Grantham (Elizabeth McGovern).

He added: "We were absolutely thrilled she was in the show but I don't really know what is coming, but I'm sure she will come back. I never know what is happening in my own life let alone the show."