Yes, it is possible to apply if you are on housing benefit. When making the application, you will need to select 'employed'.
In order to qualify you will need to provide proof that your gross monthly income equals or is larger than 1.5 x your share of the monthly rent. (For example, if your share of the monthly rent was £500, you will need to provide proof of an income of £750 a month or greater).
Applicants who are on housing benefit will be accepted if they are able to provide proof of earning 1.5x the monthly rent excluding the housing benefits contribution.