A look back at the fascinating romance between Ryan Gosling and Sandra Bullock.

In a random celebrity fact that somehow we forgot learning, Sandra Bullock and Ryan Gosling once dated.

If this particular Hollywood coupling is news to you, you are not alone. The relationship lasted from the end of 2001 to 2003 – which feels like a long, long time ago now. So we’ve deep dived.

The pair met on the set of the 2002 psychological thriller Murder By Numbers, which they co-starred in.

It was not your typical case of on-screen couple becomes off-screen couple, however. Bullock (who was 37 in 2001) played a cop chasing a young rich kid played by Gosling (then 21), who she suspected of murdering a young girl. Not exactly the recipe for romance.

But the pair became close, and first debuted as what looked an awful lot like a couple in September 2001 at the premiere of then not quite 21-year-old Gosling's film The Believer.

They were next photographed together at the Murder By Numbers wrap party in April 2002 and the following month at the Cannes premiere of the film.

The 16-year age gap turned a few heads at the time, and the pair remained pretty coy on their relationship.

In a 2003 Cosmopolitan interview, the actress dropped the word "just" so she'd be telling the truth (they could be friends and lovers after all) when she said they were friends.

"Let me see if I can answer that politically and correctly. We're friends," saying that adding "just" would "probably be a bit of a lie".

"So I'd say we're friends."

Bullock did offer up another detail on their relationship, saying that Gosling had helped her to "chill".

"I live my life at a manic pace, and he's taught me to disregard all that isn't important. He's like a little Buddha," she told the magazine.

Gosling spoke publicly of their relationship in 2011. Then outwardly single (but secretly dating now-long-term partner Eva Mendes), the 30-year-old spoke highly of exes Bullock and Rachel McAdams to The Times.

"I had two of the greatest girlfriend of all time. I haven't met anybody who could top them," he told the UK newspaper.

He also hinted at why the couple may have broken up in 2003: "Showbusiness is the bad guy.

"When both people are in show business it's too much showbusiness. It takes all of the light, so nothing else can grow."

But the split ultimately worked out best for the pair, who have gone on to build families separately.

Gosling, 37, is now in a long-term relationship with actress Eva Mendes, 44. The pair has two daughters together, Esmerelda, who is now about four-years-old, and two-year-old Amada.

Bullock, meanwhile, is dating LA-based photographer Bryan Randall, who she was seeing when she adopted six-year-old daughter Laila in December 2015. The 54-year-old is also mum to eight-year-old son Louis, who she adopted in 2010.

Want more? Here are some other celebrity couples we completely forgot about:

H/t - Decider.