[1] She made her screen debut with a minor role in the 1988 film A Fish Called Wanda.
In 1988, at the age of 24, Twomey played the role of a first junior barrister on the defence counsel in A Fish Called Wanda.
The same year she appeared in one episode ("A Present from Dublin") of All Creatures Great and Small, in which she played Molly McFeely, a short-term girlfriend of John McGlynn's character, Calum Buchanan, in addition to being the housekeeper of Skeldale House.
The following year, Twomey had another minor role, in Wonderworks: Young Charlie Chaplin, as a chorus girl.
In 2005 Twomey appeared in the Italian television series Il giudice Mastrangelo, as Jane Allison.