The band Smile was formed in 1968, by two students at Imperial College in London. Brian May and Tim Staffell needed a drummer to join them and placed a notice on the school's bulletin board. Roger Taylor auditioned for this group, and the seeds were sowed for the beginnings of a band called Queen.
Smile lasted for only two years, when Tim went off to join another band. A friend of Tim's and Roger's, Freddie Bulsara, left the band he was in and joined forces with Brian and Roger. And, so, Queen was born. The group needed a bass player and began looking.
In the very early days, Queen went through 3 bass players (one of them only for one show) before John Deacon joined them in late February of 1971. (Queen had first performed live on June 27, 1970.)
At about this time, Freddie decided that the name "Bulsara" wasn't good for a stage career and chose to take the name "Mercury" after the messenger of the gods.
With this line-up, the band had become complete. Throughout their recording career, it would remain the same. Freddie Mercury (lead vocals and piano), Brian May playing (lead guitar and vocals), Roger Taylor (drums and vocals) and John Deacon (bass guitar). In addition to these instruments, the band members frequently played additional instruments, on occasion learning new instruments for a particular song they were recording.
They released one single with the tracks "Earth" and "Step On Me"(in the US only), and a Japanese mini-album called "Gettin' Smile" appeared in 1982 which had both sides of the single and 4 studio demos. Both recordings are very rare and expensive when you do find them. There are bootleg recordings that have some of the Smile songs on them, but most of them are poor quality.
There are records around of another band called Smile that was around much later. If the recording is not one of the two mentioned above, it's the wrong band!