Gillan began acting on television doing small parts, on several drama series. Her first larger role was as a part of the ensemble cast of the sketch comedy series "The Kevin Bishop Show". She worked for the series for two years. On the programme, she played many different characters. She also played celebrities such as Katy Perry and Angelina Jolie. She was on Channel 4's 'Stacked'. She played the part of Ginny. Gillan also was on TV in a main part in a horror programme "The Well". It was broadcast as a series of short movies, on BBC Two. It was later shown on the internet.