Was there a more seminal Year of the Diva than 1998? That's when VH1 introduced its popular "Divas Live" franchise, uber-divas Mariah Carey and Whitney Houston recorded together for the first time, and a fast-rising actress named Jennifer Lopez graced the cover of this very magazine's own Diva Issue on the eve of her soon-to-be massive music career.

But nothing that year was more inescapable than Brandy & Monica's "The Boy Is Mine," a mega-duet that paired 90s R&B's two biggest breakout teen sensations for a four-minute riff-off that set a new precedent for pop vocals – not to mention female collabs. Just two weeks after its release on May 19, the song rocketed to No. 1 on the Billboard Hot 100, where it stayed for a total of 13 weeks, dominating the summer of '98. Prior to its chart success, the last female duet to top the charts was Barbra Streisand and Donna Summer's "No More Tears (Enough Is Enough)" in 1979, ending a two-decade drought that produced only a handful of diva-on-diva anthems like Aretha Franklin and Annie Lennox's "Sisters Are Doin' It For Themselves" or Lil Kim's classic "Not Tonight Remix (Ladies Night)."

To celebrate the two decades of divadom since "The Boy Is Mine," we've put together a ranking of the 20 best diva collabs of the past 20 years — as well as wag a well-manicured finger at the five worst (sorry, Shakira!). Before we dig in, a few ground rules: no boys allowed, no girl groups, each diva must sing or rap a verse of their own, and the collab must stack up against each participant's own solo work.

So call your stylist, make sure you didn't accidentally wear the same dress, and dive into our divine diva rankings.

20. Charli XCX feat. Tove Lo & ALMA – "Out Of My Head" (2017)

Charli XCX may have assembled an impressive male lineup in her video for "Boys." But she's even stronger at playing A&R for the girls on pop's fringes, many of whom (Carly Rae Jepsen, Cupcakke, Brooke Candy) she's hosted on her latest projects. This highlight from her December mixtape Pop2 is an appropriately named showcase for Charli's brain-invading hooks, and brings out the best of her Scandinavian cohorts along the way

19. Janelle Monáe feat. Erykah Badu – "Q.U.E.E.N." (2013)

Before Monáe's just-released pansexual opus Dirty Computer, there was this team-up with Erykah Badu that boldly tackled bisexual attraction ("Am I freak because I love watching Mary?"). In fact, as Monáe recently revealed to Rolling Stone, the song was originally titled "Q.U.E.E.R." An instant classic from two soul queens.

18. Christina Aguilera feat. Lil Kim – "Can't Hold Us Down" (2002)

Aguilera's 2002 album Stripped celebrated the complexities of young womanhood – the "Beautiful," the "Dirrty," and everything in between. This "Lady Marmalade" mini-reunion was a musical middle finger to gender double standards that asked the obvious: why can't ladies be players, too?

17. Mariah Carey feat. Da Brat & Missy Elliott – "Heartbreaker Remix" (1999)

The ultimate ‘90s diva helped pioneer the pop/hip-hop crossover via her collabs and remixes with rappers like Ol' Dirty Bastard and Jay-Z. This all-girl remix ranks up among Carey's very best, from the funky Snoop Dogg sample (and music video cameo) to the delightfully horny guest verses from Da Brat and Missy.

16. Reba McEntire & Kelly Clarkson – "Because Of You" (2007)

Clarkson's original was a vulnerable showstopper, tackling divorce in a way few other pop songs had done before. The country setting suits this ballad even better, with Clarkson's mama in-law Reba McEntire deftly tackling the lead verse and the octave-leaping bridge, knocking the "same damn thing" high note out of the park.

15. Britney Spears feat. Madonna – "Me Against The Music" (2003)

Though it pales in comparison to their infamous 2003 kiss in overall shock value, Britney and Madonna's duet holds up for pulling off the difficult feat of capturing a dance battle on record. Plus, you can practically hear the drool spilling from Madonna's mouth as she enjoys the glare of Spears' spotlight.

14. Rihanna feat. SZA – "Consideration" (2016)

Originally intended for SZA's own album Ctrl, "Consideration" ended up serving as the perfect mission statement for Rihanna's own ANTI ("I got to do things my own way darlin' / You should just let me / Why you won't ever let me grow?") The fact that RiRi opted to share the spotlight with SZA only highlights the greatness of both.

13. Dolly Parton, Linda Ronstadt, & Emmylou Harris – "After The Gold Rush" (1999)

This reunion of three country-rock legends almost didn't happen — originally recorded in 1994, the album was shelved for five years due to the trio's respsective promotional commitments. Luckily, the artists' fans welcomed their return, the album went gold, and the angelic harmonies of this Neil Young cover won the trio a Grammy.

12. Keyshia Cole feat. Missy Elliott & Lil' Kim – "Let It Go" (2007)

This "Juicy" summer jam marked Cole's commercial peak just as the reign of R&B (not to mention Missy) in pop radio was coming to an end. By combining three of the genre's greatest talents, "Let It Go" showcases the peak of mid-‘00s urban music and its many powers.

11. Nicki Minaj feat. Beyonce – "Feelin' Myself" (2014)

Months after unleashing the "Flawless Remix," Beyonce and Nicki re-teamed for this ice-cold stunner, which gave Queen B a chance to flex on her surprise album skills ("Changed the game with that digital drop / know where you was when that digital pop"). Also, has anyone ever been more jealous of a cheeseburger? <iframe src="https://open.spotify.com/embed/track/5fyIGoaaKelzdyW8ELhYJZ" width="500" height="100" frameborder="0" allowtransparency="true" allow="encrypted-media" class="" scrolling="no" allowfullscreen="" resize="0" replace_attributes="1" name=""></iframe>ß¿z÷×šqÿ5yíüÛ~qþýçŸuÕ·]sMºá­¶

10. Cardi B feat. SZA – "I Do" (2018)

Cardi B's star-studded debut Invasion of Privacy is an embarrassment of riches when it comes to potential Song of the Summer contenders and diva duets (including the Kehlani-assisted "Ring"). But it's hard to top "P—y so good I say my own name during sex" followed by a sizzling SZA hook.

9. Alicia Keys feat. Beyoncé – "Put It In A Love Song" (2009)

No one slept on this excellent R&B diva duet more than Keys herself, who shelved a completed music video for the track. The fact that Bey was simultaneously featured on a pair of singles with Lady Gaga probably didn't help this banger's chances of achieving the hit status it still deserves.

8. Ariana Grande feat. Nicki Minaj – "Side To Side" (2016)

The only thing more fun than listening to this reggae-lite bop is the giggles that come after you realize what the song and its SoulCycle-themed video are actually about. This duet was the climax of a hat trick for Grande and Minaj, following 2014's triple-threat "Bang Bang" and the cunnilingus crooner "Get On Your Knees."

7. Mariah Carey & Whitney Houston – "When You Believe" (1998)

On the surface, "When You Believe" could have been just a goopy pseudo-gospel promotional vehicle for a Disney knock-off. But then Carey and Houston engage in an end-of-song riff-off and you remember why it's so thrilling to hear two divas join forces in the first place.

6. Ciara feat. Missy Elliott – "One, Two Step" (2004)

Crunk&B reached its apex when R&B princess Ciara finally teamed up with Missy Elliott for this '80s electro-inspired banger. Sophisticated fun, indeed. It even inspired an equally euphoric sequel, 2005's "Lose Control."

5. Eve feat. Gwen Stefani – "Let Me Blow Ya Mind" (2001)

Just how groundbreaking was this early millennium duet, which marked Stefani's first crossover into hip-hop? It won the inaugural Grammy for Best Rap/Sung Collaboration in 2002, the only all-female track to take home the trophy in the category's 16-year history.

4. Ariana Grande feat. Iggy Azalea – "Problem" (2014)

Though she'd already scored a top 10 hit with her debut single "The Way," Grande's true commercial breakthrough came via this undeniable sax machine that also featured Azalea at her most tolerable. That it was kept from charting at No. 1 by Azalea's own "Fancy" was the only problem plaguing "Problem."

3. Lady Gaga feat. Beyoncé, "Telephone" (2009)

Beyoncé and Lady Gaga coming together was a pivotal merging of two pop eras, early ‘00s R&B and 2010s dance-pop, featuring its two queens at their creative peak. Rodney "Darkchild" Jenkins cranked up his "Boy Is Mine" digital harp again for another epic diva showdown, and brands opened up their checkbooks for a music video that was a landmark for product placement and inventive costuming. So good, Beyoncé and Gaga did it twice.

2. Brandy & Monica – "The Boy Is Mine" (1998)

Still the gold standard of '90s R&B and diva A&R, "The Boy Is Mine" was so successful it even sparked a pseudo-rivalry between its two singers that their fanbases still like to ignite from time to time. Brandy and Monica's vocals paired so well together they even tried a follow-up, the just-ok "It All Belongs To Me."

1. Christina Aguilera, Mya, Lil' Kim, & P!nk – "Lady Marmalade" (2002)

The ultimate embarrassment of diva riches — four unlikely bedfellows from pop, hip-hop, and R&B, co-produced by Missy Elliott, who did some of her best work supporting other female artists. The only reason this edges out "The Boy Is Mine" for the top slot is its super-sized ambition — and showmanship. Each singer gets their own vocal showcase, all leading up to a thunderous verse from Aguilera that nearly sweeps the rug out from all the participants. And with Xtina recently confirming that her first post-"Marmalade" duet with another pop star will be a song with Demi Lovato, the bar is still set impossibly high for other duets to scrape the melismatic heights achieved by this Moulin Rouge masterpiece.

And The Five Worst….

5. Nicki Minaj feat. Rihanna – "Fly" (2009)

Rihanna and Nicki tried so hard to make music magic as a unit they made two duets, including Rihanna's "Raining Men." Unfortunately, they were better apart than together on this generic would-be motivational anthem that finds both ladies at their sleepiest. Even the wig budget for the video looks exhausted.

4. Stargate feat. P!nk & Sia – "Waterfall" (2017)

P!nk and Sia were such no-brainer collaborators for so long, it was a bummer to see their first time on record together turn out to be this overstuffed, oversung mess that seems to have little lyrical content beyond its much-repeated title. Can we get a re-do?

3. TIE: Shakira & Beyoncé – "Beautiful Liar" // Shakira & Rihanna – "Can't Remember To Forget You"

Shakira has one of the most unique, idiosyncratic voices to cross over into pop music in the last half-century. So whenever it gets paired with another female singer, the results can often be disastrous – or worse, forgettable. That's the fate that has befallen both of her superstar duets, which are saddled by cheap production and male gaze-y videos.

2. Rita Ora feat. Charli XCX, Bebe Rexha, & Cardi B – "Girls" (2018)

How does a song like this even get released in the golden age of openly queer female artists in pop music? Ora says the song was inspired by "I Kissed A Girl," a song so problematic in its stereotypes of bisexuality that Katy Perry herself admitted she'd like a do-over. While her coming-out apology is commendable, Ora could still stand to ditch the "Red wine I just wanna kiss girls" line and recast this with Janelle Monáe, Kehlani, or St. Vincent.

1. Britney Spears feat. Iggy Azalea – "Pretty Girls" (2015)