I remember in the 1990s when Nicholas Cage became an action star to everyone's surprise that there was a lot of talk of "gee action stars are changing... these days they can be Actors as well". I think that was because in the 1980s we'd become used to muscle men being action stars - Van Damme, Norris, Arnie, etc - they'd forgotten that in the 1970s plenty of Actors went the action route, notably Richard Burton and Richard Harris.
Burton's status wasn't as surprising because he dipped in and out of action movies throughout his career - in the 1950s he appeared in Biblical epics and war films (in common with every single British star from this period). It wasn't that shocking to see him in say Where Eagles Dare.
Harris was less conventional, because he became a star later on in life - the 1960s. He did make occasional action films through that decade - The Heroes of Telemark, Major Dundee - but really got going in the 1970s: Golden Rendezvous, The Wild Geese, High Point, 99 and 44/100% Dead, Juggernaut, The Cassandra Crossing. None of these films were massive hits at the time but they seemed to do well "internationally".
And Harris actually isn't bad in these films. He doesn't look like a tough guy but he's got intelligence and soul - I particularly liked his principled mercenary in The Wild Geese. It's just darn weird that he got so many offers, that's all.