Baccara was the first act from which country to have a UK number one single?

Baccara was a female vocal duo formed in 1977 by Spanish artists Mayte Mateos (born 7 February 1951, Logroño) and María Mendiola (born 4 April 1952, Madrid). The pair rapidly achieved international success with their debut single "Yes Sir, I Can Boogie", which reached number one across much of Europe. A successful follow-up single ("Sorry, I'm a Lady") and European tour led to a number of album releases, numerous television appearances and the duo's selection to represent Luxembourg in the Eurovision Song Contest 1978.

"Yes Sir, I Can Boogie" reached the top of the charts in Germany, the Netherlands, the UK, Sweden, Belgium, and Switzerland, and number three in France. Baccara sold more than 16 million copies of "Yes Sir, I Can Boogie" and featured in the 1977 edition of the Guinness Book of Records as the highest-selling female musical duo to date. They were the first female duo to reach number one in the UK, and had the only number one by a Spanish artist in the UK until Julio Iglesias, four years later.