One is an elite members' club in London's Pall Mall and a favourite haunt of vice-chancellors and famous intellectuals. The other is a private business with bogus academic credentials that is registered in Panama but whose "international studies centre" is a postbox in the English town of Barton-upon-Humber.
But the fact that they share Athenaeum in their titles - one being the Athenaeum Club, the other Athenaeum University UK - has set alarm bells ringing that the latter is being wrongly linked with the prestigious London establishment.
Both are named after the Greek goddess of knowledge, Athena. But the connection stops there.
The first, a 180-year-old members' club that voted to admit women in 2002, is an edifice to which university heads retreat to wine, dine and discuss the latest developments in the higher education sector.
The second is an establishment that calls itself a "university" and promises degrees based on "life experience", reassuring students that the words "life experience" will not appear on the certificate.
Jonathan Ford, the club secretary, said: "The Athenaeum Club has neither knowledge of, nor any connection to, the Athenaeum University."
An investigation by The Times Higher established that the Athenaeum University UK falsely claims on its website that it is listed by the United Nations Educational, Scientific, and Cultural Organisation - the body that compiles the world list of recognised universities.
The "university" says that it has established its "incorporated branch in the UK (Athenaeum University UK)I as the International Studies Center of the university" - but the given address is a postbox on the side of a terraced house. It claims its aim is to provide its graduates "with fully recognised/ accredited" degrees - offered by a cohort who describe themselves as a "group of academicians, educators, scholars and professionals".
The organisation makes clear that it is "in no way" recognised as a university "through Royal Charter or an Act of Parliament by the UK authorities". But it claims to be "listed in the Unesco Higher Education Institutions Registry (Heir)". It adds: "Unesco is the educational arm of the UN and is recognised by the departments of education of most countries."
This week, Georges Haddad, the director of the higher education division at Unesco, said that the Heir website referred to by Athenaeum University UK had nothing to do with Unesco and that the establishment did not appear on Unesco's world register.
"Unesco has nothing to do with this," he said, adding that the similarity of name with the Athenaeum Club, and the claimed associations with learning and knowledge, could seriously mislead would-be students.
The "university's" website even refers - erroneously - to the creation of the Athenaeum gentlemen's club in 1824 by Sir Walter Scott and Thomas Moore, indirectly suggesting a connection between the two institutions.
Eric Thomas, Bristol University vice-chancellor and a member of the Athenaeum Club, said: "If there is a bogus operation capitalising on the Athenaeum name, I hope it ceases trading. It would be tragic if people were misled and relieved of cash because they assumed a non-existent association with a respected British institution."
Alan Contreras, of the Office of Degree Authorisation of the Oregon Student Assistance Commission, in the US, said that he had received inquiries from students about Athenaeum degrees.
"Even in Oregon, I have heard of the Athenaeum Club. Seems like someone is poisoning their well," he said.
The "university" is not listed on the Department for Education and Skills register of genuine education and training providers. A DfES spokesman said it would "report to Companies House any organisation that is using the word 'university' in its name without permission from the Privy Council. Similarly, we will initiate the appropriate action against any organisation that misleads students about the status of the degrees being offered".
No one from the "university" was available to comment as The Times Higher went to press. But, according to its website, Athenaeum University UK is run by Professor John S. Dovelos.
The Athenaeum Club said that he was not among its members.