On 10 December 2001, Bro'Sis released their Alex Christensen–produced debut single "I Believe" in Germany, Austria, and Switzerland. The hip hop-influenced pop song debuted at number-one in all three nations, having sold approximately 800,000 copies within its first week of release, beating previous "Popstars" winners No Angels' first week success of their debut single "Daylight in Your Eyes". While "I Believe" remained another three weeks atop the German Singles Chart, it went triple platinum in Germany, and was certified platinum in Austria and Switzerland, respectively. Altogether, the single sold around 1.5 million copies, making it one of the biggest-selling singles ever in Germany.