Jimmy Carter hasn't made any secret of it. He wants to see Guinea worm disease wiped out in his lifetime.

And now that effort’s picked up a huge assist: Britain said Wednesday it was partnering with him in the push to make Guinea worm only the second disease in history to be eradicated. The UK’s Department for International Development is providing £4.5 million (about $6.5 million) in new support for The Carter Center’s Guinea Worm Eradication Program.

The announcement from Carter and UK International Development Minister Nick Hurd came just hours before the former president has the rare opportunity to deliver a lecture in the posh House of Lords in London. Before an invited group of members of both houses of Parliament and other guests assembled in the ornate “Robing Room,” the 91-year-old Carter will discuss how tantalizingly close to total eradication the debilitating parasitic disease is.

“We started with 3.5 million cases in 21 countries [in 1986] and last year we had only 22 cases left in four countries,” Carter told the AJC in a phone interview from London on Tuesday. “We’re making good progress. But it still takes an enormous amount of effort to monitor every village that might have guinea worm and to keep it from reappearing. It’s very expensive.”

In the extraordinary press conference last summer where he discussed the discovery of cancer in his liver and brain, a grinning Carter said, "I want the last Guinea worm to die before I do." In December, the former president told his Sunday school class in Plains that a brain scan had found four cancerous lesions were gone with no new evidence of new cancer cells. On Tuesday, Carter told the AP that another scan done of his torso last week had found found no signs of melanoma.

“I haven’t had more brain scans, but I have had a scan of my chest and abdomen,” he said, adding that he was continuing with his treatment. “These last scans I had last week didn’t show any sign of recurrence of the cancer.”

While Guinea worm will be the primary focus of his lecture, Carter said he’s bringing bigger message about fighting all diseases.

“The best thing to talk about is how cost-effective this is,” he explained. “It takes an enormous amount of money each year to treat, but it’s much more efficient to spend twice as much every year and get rid of diseases once and for all. It’s only been done once before.”

Indeed, smallpox is the only human disease in history to have been eradicated — so far. Only the World Health Organization can officially certify eradication, and Guinea worm disease is a particularly tough foe: Contracted when people consume contaminated water, the disease causes a meter-long worm to emerge slowly from the patient’s body, a painful process that usually incapacitates ing them for months. There is no known medical cure or vaccine to prevent it.

Both the enormity of the challenge — and The Carter Center's record of success in confronting it head-on — are why the UK will provide this additional funding for health volunteers, water filters and larvicide in the few remaining endemic villages in South Sudan, Ethiopia, Chad and Mali, Hurd said. The money will also support surveillance campaigns in 6000 villages across these four remaining endemic countries as well as education campaigns to ensure the disease doesn't resurface.

“Guinea worm is a truly horrendous disease, causing unimaginable pain and suffering. The fact that we are now so close to eradicating it is one of the great public health success stories of modern times,” Hurd said in a statement announcing the new support package. “The tremendous progress we have made in tackling this disease would not have been possible without the personal commitment of Jimmy Carter and his Carter Center.”

The UK previously provided £30 million to the Carter Center’s Guinea Worm Eradication Program between 2009 and 2015, a fact Carter hailed in Wednesday’s announcement.

“Guinea worm eradication is possible because of the steadfast support from partners like the British government,” he said in the statement. “The UK continues to demonstrate its willingness and staying power to eradicate this debilitating disease, and today’s newest pledge is another example of DFID’s commitment.”

The progress made against Guinea worm is “a real cause for celebration,” said the presiding officer of the House of Lords in explaining the reason for Carter’s unique speaking invitation there later on Wednesday.

“It will be fascinating to hear President Carter’s experiences of taking on, and now being close to winning, the fight against an ancient disease,” Baroness D’Souza, the Lord Speaker, said in a statement.

Carter’s speech, entitled “Final Days of the Fiery Serpent: Guinea Worm Eradication” is only the second in the Lord Speaker’s global lecture series, in which members of Parliament get to hear from “international figure(s) making a real difference across the globe,” Baroness D’Souza said. The first, featuring Microsoft and Gates Foundation founder Bill Gates, took place in November 2014.

International politicians sometimes address Parliament (including President Barack Obama in 2011), “but that is usually part of a wider visit to the UK,” said Owen Williams of the House of Lords press office.

“It’s a rare thing for a foreigner to do,” Carter concurred.

But given the current intense focus on diseases like ebola and zika, this particular speaker — and his message — may be showing up at just the right time.

“A lot of people don’t think foreign aid helps anything, but it helps prevent our own people from getting diseases,” Carter told the AJC on Tuesday. “It’s time consuming and a little bit costly now, but in the long term, it’s a good investment.”

Carter's lecture starts at 17:30 GMT (12:30 p.m. in Atlanta) on Wednesday and will be streamed live on www.parliamentlive.tv. It will be followed by a question-and-answer session, which the public can submit questions to now on Twitter using the hashtag #askjimmycarter.