Each had come close: Monica's "Don't Take It Personal (Just One of Dem Days)" hit No. 2 in 1995, and Brandy's "Sittin' Up in My Room" did so in 1996.
They would finally reach No. 1 together on "The Boy Is Mine," a duet in which they snipe over the same love interest.
According to Monica, she and Brandy chose the song to make light of persistent media speculation that they were feuding. "People compared us and I never understood it," Monica told Fred Bronson for his Billboard Book of Number One Hits. "They never did that...with Brandy and Aaliyah. It was always Brandy and Monica," she said. "That's why we took the song."
Co-written by Brandy, "The Boy Is Mine" was inspired by Michael Jackson and Paul McCartney's 1982 No. 2 Hot 100 duet, "The Girl Is Mine," as well as The Jerry Springer Show, where love triangles were frequently explored.
Brandy was 19 and Monica 17 when "Boy" topped the Hot 100 dated June 6, 1998, ruling for 13 total weeks. To this day, it is Atlantic Records' longest-running No. 1.
Although both artists summited the Hot 100 again — Brandy again in 1998 with "Have You Ever?" and Monica in 1998-99 with "The First Night" and "Angel of Mine" — "The Boy Is Mine" remains each artist's biggest hit.
The two teamed up again in 2012 for "It All Belongs to Me," which reached No. 23 on the Hot R&B/Hip-Hop Songs chart. In 2017, Monica was featured on tracks by Gucci Mane and 2 Chainz, while Brandy starred as Roxie Hart in the musical Chicago. In April, she earned her first Hot Gospel Songs hit, "Ohhh Lord," with the Star cast, Queen Latifah and Patti Labelle.