Hastings and Rye MP Michael Foster has adopted a humpback whale to show his opposition to Japanese whaling.
The adoptee, named My Auntie, was brought to Mr Foster's attention by the International Fund for Animal Welfare (IFAW), which aims to protect this and other vulnerable species.
Robbie Marsland, director of IFAW UK, said: "IFAW is very grateful to Michael for showing his support for the whales. Whaling is inherently cruel - there is simply no humane way to kill a whale."
"Our scientists have analysed footage of Japanese whaling which shows whales taking over half an hour to die a very slow and agonising death. We urge the UK government and other anti-whaling nations to take diplomatic action at the highest levels to protect whales."
"I am very happy to support IFAW's campaign to protect the whales by adopting 'My Auntie,'" said Mr Foster.
The Labour MP added: "Whaling is cruel and unnecessary."
The humpback and other whales have been protected by a ban by the International Whaling Convention since 1986 after being driven near to extinction.
Nevertheless, Japan - which is not a signatory of the ban - has put 50 humpbacks and nearly 1,000 other whales on its target list. Norway, a signatory to the convention, has also been known to skirt the ban.
Japan maintains that with a population of around 40,000, growing at 15 per cent a year, the formerly endangered humpback has recovered to a sustainable level for lethal research.
Anti-whalers, on the other hand, see this as raw defiance.
"They're just doing this to show us that they can," says Paul Watson, founder of the anti-whaling Sea Shepherd Conservation Society.
As Japan sets off on its largest whale hunt to date, both Greenpeace and Sea Shepherd say that they are prepared to "chase, block, and harass" any attempts by the whaling fleet to harpoon humpbacks.