RUMOURS are rife in Hollywood that Sly Stallone and Hongkong's martial arts master Jackie Chan will combine muscle and make Rambo IV. Although Chan's manager, Willy Chan, said things were not clear cut, the Chan entourage was invited to Los Angeles by Stallone to attend the premiere of his latest film Cliffhanger and were wined and dined. ''Although there was a mention that both sides hope to work together in the future, nothing concrete has happened yet,'' Willy said. It appears the rights to Rambo IV are not owned by Stallone, and must be obtained before either superstar can agree to anything. ''A lot of things have to be worked out,'' Willy said. ''But Stallone realises that if they are going to work together the script has to have two main parts. ''Jackie won't consider a supporting role, whether it is a Rambo movie or not. ''Stallone agreed to that because he respects Jackie that much.'' The other half of the equation, aside from finding the appropriate script, will be to garner Golden Harvest's approval, where Chan is under contract. According to Willy, they have met with no reluctance from Golden Harvest regarding a meeting of the muscles. ''Everyone thinks it would be a great idea for the two dragons to work together,'' he said. Another point that would have to be hammered out would be salary. While Jackie is not on a par with the US$15 million (HK$116 million) per picture Stallone receives, he will probably command a higher salary than most Hongkong stars are accustomed to. During the LA trip, the Chans rubbed shoulders with Hollywood movers and shakers Arnold Schwarzenegger and Wesley Snipes. ''Wesley Snipes really loves Jackie,'' Willy said. ''He knows all of his movies. Not just the names, but every scene, every gimmick and every joke. He remembers everything. He was so excited talking to Jackie.'' The Chans also had an opportunity to visit the set of Stallone's new production, Demolition Man. ''Jackie was totally impressed by the set. It was huge and he couldn't believe the charges they had to pay - US$17,000 a day in rental. ''That would go a long way for a Hongkong film here.'' Although there is no timetable for negotiations between Stallone and Chan, Stallone has said he would like to come to Hongkong by Christmas. ''But if the script works out, we can fly back and forth any time. Golden Harvest has an office there [Los Angeles] anyway,'' Willy said.