It was a 104-minute (without the adverts) delight: a funny, charming, unexpectedly touching dive into a warm bath of nostalgia. If you were a fan, you really wanted it to be enjoyable.

What was particularly pleasurable was how much the six stars were obviously enjoying it too – especially David Schwimmer, who's said on more than one occasion that people wanting him to talk about nothing else but Friends can be tiresome.

He was only too happy to talk here and was frequently the most animated of the lot. He was the first of the six to walk, alone, onto the old set, torn down minutes after the finale ended but painstakingly reconstructed for this special occasion.

He was followed, one at a time, by Lisa Kudrow, Jennifer Aniston, welling up already ("Okay, where's the tissue box?"), Matt Le Blanc, a fine figure of a man whose figure has acquired a little extra padding over the years ("Remember when we all used to fit through that door?" quipped Kudrow), Courteney Cox, known to the others as either "CC" or "Court", and finally, Matthew Perry, who was greeted with a "Could you BE any later?" from Aniston. See! Even the friends themselves do that joke.

There was a lot of speculation about Perry's slurred speech when the trailer for the reunion was released. We've since learned he had serious dental surgery just hours before the programme was recorded last month. Mystery solved.

The show bounced back and forth between distinct segments. The six sat in Monica's "apartment", just like in the old days, chatting about... well, the old days. It almost felt like eavesdropping.

There was an interview and Q&A session conducted by James Corden in front of a live audience, with the famous title-sequence fountain as a backdrop. There were table readings of favourite scenes, intercut with clips from the originals. It was fun to see the actors slide effortlessly back into character, as though all of them (and not just Ross and Rachel) had been on a break.

There was a quiz section with Schwimmer firing questions about the show at the others. The stars of Friends would never win a Friends quiz, that's for sure. Nobody could remember Monica and Rachel's grouchy downstairs neighbour was called Mr Heckles. Then Mr Heckles, played by Larry Hankin, appeared.

There were also crowd-pleasing appearances by Maggie Wheeler (Janice), Tom Selleck (Richard), Thomas Lennon, who played Joey's hand twin, Elliott Gould and Christina Pickles (Ross and Monica's parents), and, via video link, James Michael Tyler (the lovelorn Central Perk owner Gunther).

Lady Gaga joined Kudrow to duet on Phoebe's signature song, Smelly Cat. The guest spots were brief, though. They had to be, because there was a lot to cover here. The revelations, some small, some big, came thick and fast.

We learned Cox used to stash lines of dialogue in the basket of apples, or write them on the furniture, and that Schwimmer had to be coaxed into playing Ross, because he'd grown disillusioned with television and had retreated back to the theatre.

We discovered everybody hated the monkey, which was less than professional in its attitude. The biggest reveal of the show? That Schwimmer and Aniston had serious crushes on one another during the first season. Nothing happened (off-screen), since they both always seemed to be involved with other people.

Series creators Martha Kauffman, David Crane and Kevin Bright talked about where the idea came from, who was cast first, and how they initially underestimated how big a "thing" the Chandler-Monica relationship was with viewers – and promptly changed course in the next season.

There were hilarious outtakes and wonderful behind-the-scenes footage, never seen before, including the actors' emotional reactions when the director called "Cut!" for the very last time on the very last episode. Everyone was in puddles of tears.

There were puddles forming by the end of the reunion show, too. If anyone ever puts a title on it, it will be: 'The One Where They All Cried at the End'.

But the prevailling mood here was one of joy. Kudrow, on behalf of the group, killed stone dead the possibility that there will ever be a Friends revival. Nobody wants to ruin the perfect, happy ending.

Friends: The Reunion was perfect, too, a worthy final farewell, 17 years on, to a great and beloved series.