Queen stars Brian May and Roger Taylor have confessed their world tours with Free singer Paul Rodgers was "a stretch" at times because the rock veteran wasn't a natural fit for them. The duo joined forces with Rodgers a decade ago and toured the world twice as Queen with Paul Rodgers, and released the album The Cosmos Rocks in 2008, but, as May and Taylor prepare for a string of North American dates with new frontman Adam Lambert, they have revealed they're much more comfortable with their latest replacement for dead singer Freddie Mercury. Taylor tells the Toronto Sun newspaper, "Paul has one of the greatest rock voices but it’s more blues and soul orientated I would have thought. I would say, with all due respect to Paul, that Adam is more suited to a lot of our material and, whereas we had great tours with Paul, I think Adam is more naturally at home with us." May adds, "I think the styles match more closely in a sense. But we had a great time with Paul no doubt about it and it kind of stretched it to a new place and I think a thoroughly good experience. But Adam... has many, many colours, so we can explore some of those strange excursions that Queen likes to." Meanwhile, May reveals the group's current tour with Lambert, who auditioned for American Idol with Queen's Bohemian Rhapsody, could be its last. He explains, "I don’t know how long we’re going to be capable of doing this kind of thing. At the moment it is that feeling of 'Yeah, One last swing around, one last gallop', and we’ll see how it goes."