The six co-stars of NBC’s smash hit Friends, the top-rated comedy series on US television, say emotions are running high on the set as they near production of the show’s final episode.‘‘We’re like very delicate China right now, and we’re speeding toward a brick wall . and inevitable pain,’’ Jennifer Aniston (aka Rachel Green) told television critics gathered for a question-and-answer session with the cast on Tuesday in the Warner Bros. TV studio where the series is filmed.‘‘And we’re going to smash into a million pieces,’’ added Lisa Kudrow, best known as Phoebe. ‘‘It’s a deeper loss than I was expecting.’’ The six performers, seated together in director’s chairs, struggled to articulate how they felt to be bidding goodbye to a show that has been central to their lives — and a centrepiece of prime-time TV — for 10 years.Matt LeBlanc said he felt the weight of leaving behind an endeavour that has occupied ‘‘a third of my life’’. LeBlanc will be reprising his role as Joey in an upcoming NBC spinoff planned for next season.David Schwimmer, who plays Ross, said a key to the longevity of Friends was the real-life bond among the co-stars. ‘‘We really liked each other from the beginning. We were very lucky.’’And Matthew Perry, the show’s wise-cracking Chandler Bing, said all of them realised that Friends will be a tough act to follow. Courteney Cox Arquette, who plays Monica and revealed last week that she is pregnant in real life, said she looked forward to motherhood to keep her busy post-Friends. Neither the show’s producers nor the cast would say much about how the series ends. The studio audience will be barred from key scenes when the finale is shot on next Friday, and only essential personnel will be allowed on the set in a bid to keep the conclusion secret until it airs in the spring.Schwimmer insisted the finale would leave fans satisfied. ‘‘We will end up with a sense of a new beginning, and the audience has a sense that it’s a new chapter in all of their lives,’’ he said. —(Reuters)