Ashton Kutcher and Mila Kunis' 'That 70s Show' co-star wants to be a bridesmaid at their wedding.

Laura Prepon - who worked on the comedy show with the couple - would love for them to get married so she and the whole cast, which also included Topher Grace, Wilmer Valderama and Danny Masterson, can attend.

She told the New York Daily News: ''Of course I will [be there]. Are you kidding? All of us are going to be right up there on the altar.''

Mila, 29 and 35-year-old Ashton have been staying in London while the actress shoots 'Jupiter Ascending' and have reportedly become so besotted with England they want to tie the knot there once Ashton's divorce from Demi Moore comes through.

A source said: ''Mila and Ashton have fallen in love with the UK. They are desperate to get married as soon as possible because they want to start a family and are slightly old-fashioned about these things.

''Mila loves the idea of a stately home or something in the English countryside.''

Despite considering lavish venues for the big day, the couple want the ceremony itself to be ''low-key'' with only a few select guests witnessing the nuptials.

The source added: ''Although the venue may be spectacular, the wedding itself will be low-key. It's expected it will be just Ashton, Mila and a few family friends.''

Although the couple are yet to announce their engagement, things have progressed between them recently, as Mila introduced Ashton to her parents, Elvira and Mark, when they came to visit her in the UK at the end of May.