Pet Shop Boys (no 'the') are an English duo of Neil Tennant (vocals, keyboards) and Chris Lowe (keyboards, vocals). The group formed in 1981 and were originally called West End (after the section of London), before changing their name to Pet Shop Boys, after a friend who actually worked in a pet shop (and was a boy).
In 1983, the duo met New York producer Bobby Orlando (Bobby O); they were big fans of his dance-driven productions. Bobby O agreed to produce some Pet Shop Boys songs, and worked on 11 songs, including "West End Girls," which became a minor U.S. club hit. The group dropped Bobby O in 1985 (only after agreeing to pay him of cut of their royalties) and signed to EMI/Parlophone.
By the way, Bobby Orlando was also the producer/creator of The Flirts. (!)
Pet Shop Boys remixed the Bobby O songs for their major label recordings, and went on to become big stars. "West End Girls" became a #1 hit in the U.S. and U.K., and their 1986 debut LP, Please, broke the top 10 in both countries. The duo would go on to have 42 top 30 singles in the U.K. and 6 top 40 hits in the U.S. They have sold more than 50 million units over their career and remain active as of their writing.
The original "West End Girls" video is below. Note that the song was inspired by the T.S. Eliot poem 'The Waste Land.'