The 29-year old has signed a three-year deal with the Baggies, joining as a free agent after leaving Werder Bremen, and Clarke is thrilled about his arrival at The Hawthorns.
"Markus is an experienced striker who has scored goals in three of Europe's top leagues, as well as in the top European competitions," he told the club's official website regarding the former Malmo, Racing Santander and Ajax attacker.
"Now he is determined to prove himself in the Barclays Premier League.
"Markus will really increase competition for places in the forward areas and hopefully spur on the strikers we already have here.
"He had several other offers this summer but he made it clear that joining West Bromwich Albion was his first choice and we're really pleased we've been able to conclude a deal."