THIS could be the end of a beautiful Friendship. But will Rachel, Phoebe, Monica, Joey, Chandler and Ross really say goodbye after the final episode of Friends is screened on American television in May?

They say yes. Past experience says no. Actors are rarely able to leave well alone and completely divorce themselves from a successful project. They may only return temporarily to old stamping grounds, but generally the sound of a large cheque being waved under their nose is enough to make them play it again, Sam.

The rumours have already started that Friends Reunited is being planned before the final, top secret episode of the US comedy is shown. The cast has said before that "this series is the last" before huge salary hikes helped change their mind. As a result, they've been collecting a cool $1m apiece for each episode in the tenth season.

The appeal of making Friends again has been strengthened by the six main cast members' mostly faltering attempts to establish themselves on the big screen. Their movies have mostly done poorly at the box-office.

Who can't believe that one day Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, Matthew Perry and David Schwimmer won't be tempted to pay another visit to Central Perk coffee shop?

There were stories that the six would shoot a 90-minute Thanksgiving special immediately after completing filming on the last series. The actors deny that's planned. "A reunion? We haven't even left yet," Aniston has said. The cast joked that they'd accept $4m each to do the special. In a few years time, if they haven't scored big away from Friends, they may be glad to return.

Matt LeBlanc is already committed to continue playing his character in a spinoff comedy, Joey. Don't be surprised to see his old friends popping up from time to time in the series to support him.

Even if no new episodes are made, Friends will be on screens for years to come in syndication. Channel 4's constant re-running of episodes has proved that British fans will watch the same scenes over and over again.

Two other top US comedies take a farewell bow this season, Frasier and Sex And The City. Frasier, about a Seattle-based radio psychiatrist, ends in May after an 11-year run. Before that Kelsey Grammer played Frasier in the bar-room comedy Cheers.

The TV network has been contemplating Frasier's demise for some time. The current season was expected to be the last, but only confirmed this week. Executives had kept their options open for a show for which Grammer pocketed a reported $1.6m dollars an episode, making him the highest paid sitcom star on TV for a time.

He says that both cast and creative team felt it was the right time to sign off. Whether they'll still feel the same in a few years time is debatable. Past form suggests Frasier and those outrageous Sex And The City girls will come back in some form in the future.

Grammer has spent two decades as the shrink, as long as James Arness spent packing a gun and marshal's badge as Matt Dillion in Gunsmoke. The western series ended in the 1975 but nearly two decades later Arness, by then in his early seventies, was still playing the law enforcer in TV movies. Even a spell in another TV western, How The West Was Won, didn't stop him returning to Dodge City regularly in the 1980s and 1990s.

Dennis Weaver handed in his badge as Marshal Sam McCloud in 1987. Twelve years later, he was back - this time as a US senator - in a McCloud TV movie.

Shabby detective Columbo solved murder cases during the 1970s. Then actor Peter Falk pulled on his dirty raincoat again for fresh investigations in the 1990s. Female detective duo Cagney And Lacey couldn't keep away either, returning to the mean streets of New York a decade after quitting TV screens in 1988.

The British can't leave well alone with comedies, probably because finding a new series that makes people laugh is so hard. Sometimes it works. The Likely Lads were successfully revived, and even improved upon, by Dick Clement and Ian La Frenais as Whatever Happened To The Likely Lads?

Sometimes it doesn't. Original stars Polly James and Nerys Hugh re-united as The Liver Birds in 1996, but reaction was muted and another series wasn't forthcoming..

Perhaps the strangest revival concerned The Fall And Rise Of Reginald Perrin. As star Leonard Rossiter had died, the new series re-assembled other original cast members for The Legacy Of Reginald Perrin. On that basis, any reluctance by the Friends stars to return needn't have to be a problem after all - the series could be made without them