Seth Rogen poked fun at his love of marijuana while testifying before a US Senate subcommittee.

The 31-year-old actor, who has frequently spoken of his fondness for the drug, visited Capitol Hill in Washington D.C. on Wednesday (26.02.14) to voice his support for legislation to increase funding for Alzheimer's disease, which his mother-in-law, Adele Miller, was diagnosed with at an early age.

Speaking at the hearing, the 'Pineapple Express' star said: ''First I should answer the question that I assume many of you are asking - yes, I am aware this has nothing to do with the legalisation of marijuana. In fact, if you can believe it, this concerns something that I find even more important.

''I started dating my wife Lauren nine years ago when her mother was almost 54 years old. It was during this trip, the first time I met my now mother-in-law, that Lauren first admitted to herself and then to me that something was off with her mother.

''Soon after this trip at 55 years old Lauren's mother was diagnosed with early onset Alzheimer's.''

The 'Knocked Up' star praised his father-in-law for making Adele comfortable as her disease progresses and opened up about his decision to start his own fund, 'Hilarity for Charity,' to support other families and research on the illness.

He said: ''That's right, the situation is so dire, that it caused me, a lazy, self-involved, generally self-medicated man-child, to start an entire charity organisation.''

He added: ''I came here today for few reasons. One I'm a huge 'House of Cards' fan. ... Two, people need more help. I've personally witnessed the massive amount of financial strain this disease causes. ... Three, to show people they are not alone, so few people share their personal stories.''

Ben Affleck also spoke about the Democratic Republic of Congo at Capitol Hill on Wednesday.