Bros's debut single, "I Owe You Nothing", was released in August 1987, but it only peaked at number 80 on the UK Singles Chart. However, their breakthrough came with the release of their second single, "When Will I Be Famous?", in November 1987. The song reached number two in the UK, and number one in Ireland. The song also reached the top ten in 10 other countries across Europe and Australia and peaked at number 10 on the US Billboard Hot Dance Club Play chart.

Their first UK tour, known as Bros Push Live, sold out 14 shows within an hour of the tickets going on sale. Due to the demand, extra dates were added.^[

The group's popularity was named "Brosmania" by the music press, and they're following of teenage girls were known as "Brosettes". In September 1988 the Metropolitan Police had to close off part of Oxford Street in central London when an overwhelming number of fans turned up to a record signing by the band at the flagship store of record shop HMV. Bros had over six million fans worldwide join the band's fan club, known as the Bros Front. With such demand for merchandise and fans wanting to talk to their idols, a phone line was set up, with 70,000 fans using the service within the first month.