They won the hearts of fans around the world as Chandler Bing and Monica Geller, whose drunken one-night stand ends up blossoming into a happy marriage.
Offscreen, Matthew thought Courteney was ‘cripplingly beautiful’ when they first met after being cast on the smash NBC sitcom in 1994.
This week, devastated by Matthew’s death, Courteney wrote on Instagram: ‘I am so grateful for every moment I had with you Matty and I miss you every day.’
But did Chandler and Monica’s TV romance ever spill over into real life?
In his memoir Friends, Lovers And The Big Terrible Thing, Matthew revealed he was bowled over by how attractive Courteney was when he first saw her in person.
Reflecting on their first meeting, he wrote: ‘Courteney Cox was wearing a yellow dress and was cripplingly beautiful.’
It was Courteney who made the first moves to ensure that the TV friend group also developed a sense of camaraderie offscreen.
She went so far as to arrange poker games for the six principal cast members – the three women and Matthew, plus David Schwimmer and Matt LeBlanc.
But at that time, there was only the slightest hint on the series that Chandler and Monica would become an item – and no spark between Courteney and Matthew.
In fact Matthew ‘was still crushing badly on Jennifer Aniston,’ the residue of his abortive attempts to woo her years prior.
Three years before Friends, he had asked her out, and when she gently turned him down and said ‘she’d love to be friends with me’ he snapped: ‘We can’t be friends!’
Then Matthew and Jennifer both booked the sitcom that launched them to worldwide superstardom, and he found himself on set everyday attempting to place limits on how long he gawped at her so as not to be too obvious.
In 1998, four years after Friends began, Jennifer started dating her first-husband-to-be Brad Pitt and Matthew finally got over his infatuation with her.
That same year, Chandler and Monica embarked on what became the show’s most lasting romance, defying even the writers’ initial expectations.
The creators originally meant for the characters to spend just one night together – but the audience fell in love with the pairing, and the trajectory of the series was rerouted to give them a real relationship.
Depressed about being single the night before her brother Ross’ wedding, Monica gets roaringly drunk and falls into bed with a comforting Chandler.
Their sexual chemistry turns out to be irresistible, and they start sneaking around and meeting for liaisons in what is initially a friends-with-benefits situation.
But in short order, their pals get wind of the dalliance in a fan favorite episode called The One Where Everybody Finds Out.
When he is finally confronted about the affair, Chandler blurts out that ‘I’m in love with Monica!’ – and Monica tells him she loves him back.
In an interview with Diane Sawyer last year, Matthew revealed he at one point or another became besotted with each of his female co-stars on Friends, saying warmly: ‘How can you not have a crush on Jenny and Courteney and Lisa?’
However he, David and Matt spilled to Access in 2021 that the cast had a ‘no hook up rule’ laid down by director Jim Burrows.
‘There was a rule that we had, it was really important to the six of us, that we kept a friendship, that we were friends,’ Matthew explained.
If any of their relationships escalated beyond a platonic level, the results might have been a ‘strangeness’ that could ‘mess with things,’ he added.
During the late 1990s, Matthew was given Vicodin after a skiing accident and then spiraled into a drug addiction so overpowering that he later confessed he could barely remember whole seasons of Friends.
While Jennifer was the most proactive in her attempts to ‘reach out,’ Matthew shared that the whole cast noticed the problem and rallied around him.
As Matthew battled his demons, Courteney was pursuing a romance with David Arquette, her steamy co-star in the 1996 slasher classic Scream.
The couple tied the knot in 1999 and she changed her credit on Friends to Courteney Cox Arquette, which is what it remained until the show ended in 2004.
However, in 2015, rumors began swirling that Courteney and Matthew had struck up a romance in real life, over a decade after Friends came to a close.
Courteney by that point had been divorced from David for a couple of years, and was in the midst of an off period in her on-off romance with Johnny McDaid.
However an Entertainment Tonight insider left fans crestfallen by revealing that the conjecture about her and Matthew was ‘untrue.’
Yet after the show ended, it was once again Courteney who helped facilitate the lingering bond among the cast, Matthew shared.
‘We try to get together when we can,’ he told BuzzFeed. ‘Courteney is a great host, and she has a nice place in Malibu, and we try to go out there as often as possible. But the six of us haven’t been in a room together for a number of years.’
A few days before Halloween this year, Matthew was found dead in his hot tub at home at the age of 54, reportedly having drowned.
Over the years, Matthew was open about his struggles with drugs and alcohol, but initial toxicology reports revealed he had no meth or fentanyl in his system when he died, and the authorities did not unearth illegal drugs at his house.
He did have prescription drugs at home, including anti-depressant and anti-anxiety medication, according to a law enforcement mole who spoke to TMZ.
After attending his funeral along with the rest of the Friends cast, Courteney posted a heartrending Instagram tribute to him this week.
Her message was attached to a blooper from the Friends scene in which it first emerges that Chandler and Monica have slept together.
Ross bursts into Chandler’s hotel room, crowing that he is about to get married while Chandler carefully keeps his bedclothes held up high.
After Ross leaves, Monica pokes her head out from under the duvet and asks: ‘Do you think he knew I was here?’ eliciting a huge applause break.
In the outtake, Monica waits for the cheers to die down and then tells Chandler: ‘Okay, your turn,’ prompting both of them to vanish back under the covers.
Courteney then breaks character, emerges from under the sheets and laughs, telling the audience that Matthew told her to add that line.
‘I am so grateful for every moment I had with you Matty and I miss you every day,’ Courteney heartbrokenly wrote next to the clip.
‘When you work with someone as closely as I did with Matthew, there are thousands of moments I wish I could share. For now here’s one of my favorites,’ she explained.
‘To give a little backstory, Chandler and Monica were supposed to have a one night fling in London. But because of the audience’s reaction, it became the beginning of their love story,’ Courteney shared.
‘In this scene, before we started rolling, he whispered a funny line for me to say. He often did things like that. He was funny and he was kind.’