IT was a double delight for BBC's Casualty when five-month-old identical twins from Hereford joined the cast for two episodes.

Charlotte and Sophie Williams played baby Nicole, the unknown daughter of a student nurse, Roxanne, who is due to appear on our screens in April.

With no history of twins on either side of the family, the girls came as somewhat of a surprise to Gwyn and Emma Williams and they enrolled them with TAMBA, the national twins association, immediately.

When Casualty wanted the association to find identical twin girls for a future episode, TAMBA contacted the Williams' as one of four possible sets of twins and the girls got the part.

Eight days on set

Mrs Williams accompanied the pair to Bristol for eight days of shooting and even got teething advice from 'Duffy', played by Cathy Shipton, who brought her daughter Talula on to the set especially to meet them.

Both girls had little notebooks sporting their names and all of the cast signed and wrote messages in them including their screen mum as a keepsake for the girls when they are older.

The crew surprised Mrs Williams when they requested an extra day of filming. She said: "We definitely could not attend. They offered to send a chaperone in a taxi to collect our daughters and take them to Bristol without us.

"I assume whoever suggested that is not a parent themselves. As if! In the end they found a baby double in Bristol, who looked very similar to Sophie and Charlotte."

The pair behaved very well - but for those rare occasions when the stress of stardom was too much they had a doll as their own special stand in!

Although the Williams' were treated like royalty and had an interesting experience, Mrs Williams decided that the girls' debut performance was more than enough to cope with.

"The girls are very chilled out," explains Mrs Williams. "It was a nice chance for them."

The two episodes will be screened on June 1 and 8.