Which Beyoncé song features the rapper Jay-Z and opens with a sampled horn line?

Beyoncé's song featuring Jay-Z and opening with a sampled horn line is “Crazy in Love.”

Released in 2003 as the lead single from Dangerously in Love, the track combines Beyoncé's R&B singing with a rap verse by Jay-Z. Its prominent brass hook samples “Are You My Woman (Tell Me So),” a 1970 song by the Chicago soul group the Chi-Lites.

The song was produced by Rich Harrison and Beyoncé, with Jay-Z contributing his rap. Its energetic arrangement and instantly recognizable horn figure made it a defining early-2000s pop and R&B recording.

“Crazy in Love” reached number one on the Billboard Hot 100 and became Beyoncé's first solo US number-one single. It won two Grammy Awards at the 2004 ceremony, for Best R&B Song and Best Rap/Sung Collaboration. The music video, directed by Jake Nava, is also remembered for its choreography and fashion imagery.