A British university student said he spent a day glued to a giant billboard to help promote a bestselling book, "This Diary Will Change Your Life."

Dave Lions, 19, said he spent Tuesday stuck to the London billboard to raise money for his education in engineering, The Sun reported Wednesday.

Lions said that while unconventional, his living advertisement gig was not necessarily uncomfortable -- he described his experience of the day as "like being stuck under a huge duvet."