This Friday sees the release of Behind The Candelabra, which deals with the story of Liberace and his secret gay lover. Difficult to believe now, but back in the day Liberace's sexual orientation wasn't exactly common knowledge, and it was believed that if he came out of the closet, his fans would all abandon him. As you can imagine, he had to keep his boyfriends a top secret.

Here are five other famous couples that decided to keep their love on the down-low.

Having met on the set of the first Twilight movie, it was a surprise to absolutely nobody that R-Pattz and K-Stew were hooking up. But despite this, they never officially announced they were dating, perhaps to keep the "will-they-won't-they" element to their on-screen relationship. In fact, the first public declaration of that they were even an item came when Stewart apologised for cheating on him with Snow White & The Huntsmen director Rupert Sanders.

When they hooked up the first time, it was all well and good, two hot pop-stars dating each other. Fine. But then it all went to hell. After the ... unpleasantness, they broke up (obviously). But then suddenly Brown was a featured artist on one of Rihanna's singles, and after a while they confirmed they were dating again. In the gap between that however, it was heavily rumoured that Ri-Ri was seeking comfort in the arms of frequent collaborator Drake. Rihanna and Brown have since broken up (again), so we'll see what happens next.

Bonnie & Clyde '03. Crazy In Love. Déjà Vu. Upgrade U. We knew watching all of these music videos what they were up to, but it wasn't until they got secretly married in 2008 that they finally revealed they were, ye know, a thing. Never fully expressing why they decided to keep it schtum - although the press aspect of it probably played a big part in it - they've kept up the minimum access to their private lives aspect rather well in their five years married.

Proving that hush-hush love stories aren't just a modern occurrence for celebrities, Tracy and Hepburn's secret 27 year relationship is the benchmark that all others must be compared to. When they met Tracy was still married but no longer living with his wife, but in order not to upset her, he kept his relationship with Hepburn a secret. When he fell ill, Hepburn took a five year break from acting to remain by his side, but out of respect for his family and wife, did not attend his funeral. Only after Tracy's wife died did Hepburn publicly acknowledge their relationship.

Roberts has had a string of would-be suitors; Jason Patrick, Liam Neeson, Matthew Perry, Kiefer Sutherland, she was even married to singer Lyle Lovett. But while on set for The Mexican - and still dating Benjamin Bratt - she fell in love with cameraman Daniel Moder. However, Moder was married at the time, so they kept it to themselves until a year later when he got a divorce, and then in 2002 Roberts and Moder got married. They're still happily married today with three kids. See? Love wins out in the end!