1994 was a big year for music. The radio-friendly rock of Alice in Chains, Pearl Jam, R.E.M., Soundgarden had the edge in the US and UK charts; Kurt Cobain's suicide, Oasis vs Blur, Michael Jackson's marriage to Lisa Marie Presley and the Rolling Stones' Voodoo Lounge world tour all dominated the headlines that year. At the same time, US hip-hop and R&B continued its major assault on the global music business with a string of blockbuster releases from artists including Snoop Doggy Dogg, Warren G, Boyz II Men, Nas and Usher.

The monopoly of male artists in the charts was challenged by astonishing debuts from Aaliyah (Age Ain't Nothing But A Number) and Brandy (self-titled), whilst Mary J. Blige's sophomore album My Life was widely acclaimed as a ground-breaking work and SWV continued their run as one of the most popular R&B groups of the decade.

The real success story of '94, however, belonged to the all-female soulful hip-hop and new jack swing trio TLC, formed in Atlanta, Georgia four years prior.

By the time Tionne 'T-Boz' Watkins, Lisa 'Left Eye' Lopes and Rozonda 'Chilli' Thomas began to record their second full length release CrazySexyCool in 1993, they had already won over millions of US music fans following the 1992 release of their debut Ooooooohhh... On the TLC Tip.

The crack team of key players in the early '90s hip-hop and R&B boom assembled to co-write and co-produce TLC album #2 included one Sean 'Puffy' Combs, Kenneth 'Babyface' Edmonds, Dallas 'The Manipulator' Austin and Jermaine Dupri. Puffy had already produced Notorious B.I.G. and Mary J Blige, Babyface had songwriting credits across a ton of artists including Bobby Brown and Mariah Carey, Dallas Austin had been behind tracks by Grace Jones, George Clinton and Boyz II Men whilst Jermaine Dupri's fingerprints were all over hit records by artists including Kriss Kross, Run DMC and Shanice.

TLC's move away from the anthemic funky hip-hop of their debut in the direction of a smoother, sensual and developed sound owed much to the power and influence of the collective of composers, engineers and producers working on the record; Left Eye's high-profile conviction for arson and subsequent lengthy stay in rehab for alcohol abuse also had an unexpected effect on the LP's style.

Owing to the terms of her sentence, the rapper's time in the studio with T-Boz and Chilli during the recording of CrazySexyCool was limited to a handful of sessions, and as a result Lopes' contribution to the final version was minimal, leaving it notably short of the rapped verses of sharp lyrics that had helped to characterise the early TLC sound.

Aside from producing some of the best slow jams from the late twentieth century, the album featured guest spots from Busta Rhymes on 'Can I Get A Witness (Interlude)', a Southern drawled verse from then fresh-faced labelmate André 3000 in 'Sumthin Wicked This Way Comes', samples from Slick Rick on 'Hey Young World' and Jean Knight throughout 'Switch' as well as backing vocals from a then unknown Cee-Lo Green on the Prince-inspired 'Waterfalls'.

One of four singles from the album to make the US top 5, 'Waterfalls' went on to spend seven weeks in the American number one spot in 1995, also charting high across the world. The single's accompanying video, which received heavy rotation on MTV and in the UK, was regarded as an absolute game-changer for its overt messages around safe sex, drug and HIV/AIDS awareness, footage of sexual partners and overt lyrics such as:

"One day he goes and takes a glimpse in the mirror and he doesn't recognise his own face / His health is fading and he doesn't know why / Three letters took him to his final resting place."

T-Boz, Left Eye and Chilli had been taping wrapped condoms to their Cross Colours clothes as fashion accessories with a conscious message since 1992, and were well-known promoters of safe sex, reportedly influenced by Chilli's experience of an unplanned pregnancy and subsequent abortion.

But CrazySexyCool wasn't an exercise in preaching TLC's beliefs around lifestyles, nor did it overtly assert views on issues which mattered to the group. This was smart cool pop rooted in music of black origin, made for young music fans who wanted to emulate or acquire the dress code, the choreographed moves, the attitude and the confidence that the three members possessed. TLC were the role models of their generation - perhaps unwittingly at first - who bridged the gap between contemporaries like Salt-N-Pepa, Toni Braxton and Janet Jackson.

Skits like 'Sexy interlude' aside, in which Combs gets prank-called by the gang, the record glistens with sleek production, themes of love, lust, sex, friendships and empowerment wrapped up in deep, slow beats, long drawn-out '90s synthesised strings and soft piano melodies. 'Red Light Special', 'Let's Do It Again' and 'Let's Take Our Time' are 100% hot; intense, sugar-sweet and lip-biting tracks a breath away from a Parental Advisory sticker.

Uptempo inclusions 'Case Of The Fake People' and all-time TLC classic 'Switch' aren't so much anomalies on the album, more welcome respites from the continual heat. One is a tempered down boom bap lesson on the perils of negative friendships, the other a brilliant paean to independence, self-confidence and trust in relationships that includes the killer line, "At the hotel motel Holiday Inn / I said if your man starts actin' up, switch and take his friend," derived from a lyric in the Sugarhill Gang's 'Rapper's Delight."

Five years after its release, CrazySexyCool was certified Diamond by the Recording Industry Association of America (RIAA), indicating sales of 10 million units or more - 10 times platinum. As of 2014, the record has sold in excess of 23 million copies, meaning the CD or vinyl is owned by more music fans than Prince's Purple Rain (20 million), Green Day's Dookie (20 million) or Madonna's Like A Virgin (21 million).

Statistically speaking, TLC is still one of the most successful female groups of all time. Stylistically speaking, as pioneers of a soulful hip-hop and R&B crossover style that conquered the globe throughout the 1990s, TLC directly influenced and paved the way for acts like Missy Elliott, Destiny's Child, The Spice Girls, Pussycat Dolls, Lil' Kim right through to the current crop of pop artists with R&B and hip-hop sensibilities such as Rihanna, Nicki Minaj, Janelle Monáe, FKA Twigs and Azealia Banks.

The TLC story took a darker turn beyond the success of the double Grammy Award-winning CrazySexyCool and follow up records FanMail and 3D, the group's career marked by financial problems, infighting and most significantly, the tragic death of Left Eye in a car accident in 2002. The two remaining members T-Boz and Chilli parted soon after to pursue solo interests, before reuniting for a series of projects including sporadic appearances at festivals, American Idol performances, for TLC tributes and documentaries and to promote a greatest hits compilation. Earlier this year, the duo announced they were working on a fifth studio album, release date unknown.

The challenges and loss faced by TLC were numerous, least of all as an all-female group navigating a course through a tough and unforgiving male-orientated music business in the early to mid-90s. Whether they realised it or not, by virtue of the talents and character they possessed, the team of composers and producers around them, the shift towards a new force in R&B, pop, hip-hop and soul, with CrazySexyCool T-Boz, Left Eye and Chilli created an important cultural work of its time that is still relevant twenty years on.

In a recent interview about the album's anniversary, Chilli spoke candidly, saying "We were defining each girl's personality with the album, and that was really exciting. For us, CrazySexyCool was something we felt that every woman possessed... it was just something that naturally happened. That album was the defining moment for each girl. We were really happy and we still are really happy to be the voice for so many women in so many different situations in their lives. I wanted us to be the biggest girl group ever, and that happened, and I was very happy."

TLC, we salute you.