Biggest celebrity stories of 2015: Caitlyn comes out, Charlie Sheen's HIV bombshell and Zayn goes another direction

It is safe to say that the last 12 months have been memorable for the residents of Tinsel town. For some stars, this year was all about reinventing themselves and sorting out their public image. So before we head into the new year, let's look back at the five biggest celebrity events of 2015.

Charlie Sheen's HIV announcement

In November, the 50-year-old Hollywood actor confirmed he was living with the virus.

In an appearance on NBC's Today show, the former Two And A Half Men star, revealed he was diagnosed with the infection "roughly four years ago" and had been held ransom by people he once considered friends.

He is now facing a $1m lawsuit from his ex-fiancée Brett Rossi, who claims that he failed to disclose his health condition while they were dating.

Caitlyn Jenner comes out as transgender

After 65 years as a man, Caitlyn Jenner made her debut on the cover of Vanity Fair magazine back in June.

The former Olympian, who is the step-parent of Kim Kardashian, provoked a social media buzz with the cover story which featured the headline "Call Me Caitlyn" and showed her wearing a cream corseted bodysuit.

She celebrated her new life months after coming out publicly in an interview with Diane Sawyer.

Death of Bobbi Kristina Brown

In July, the surviving child of Whitney Houston and Bobby Brown passed away at Atlanta's Peachtree Christian Hospice, almost six months after she was found unconscious in a bathtub.

The 22-year-old died three years after her mother's life was also cut short in 2012, when the I Will Always Love You singer drowned in a bathtub at the Beverley Hills hotel.

Zayn Malik quits One Direction

In March, the Bradford-born heartthrob sensationally quit the British boyband telling the world that he just wanted to be "a normal 22-year-old".

However, within weeks he had gone solo and started bragging about making 'real music'.

His departure is said to have acted as a catalyst for One Direction's imminent split.

Adele's record-breaking comeback

The British powerhouse stormed back onto the music scene in November after a four-year hiatus to drop her eagerly-anticipated album 25.

Days after unveiling her comeback single, Hello, the 27-year-old songstress soared to number one in the charts. 25 has since broken every record including becoming the fastest-selling album of all time after shifting 3.3 million copies in its first week in the US.