Afghanistan finished second in the Pepsi ICC World Cricket League Championship last week and along with Ireland progressed to ICC's flagship event that will be staged from February 14 to March 29 in Australia and New Zealand.
Afghanistan is in Pool A while Ireland is in Pool B.
Clarke, whose side beat Afghanistan by 66 runs in the only ODI between the two sides to date in August 2012, was delighted for the Associate side.
"To obtain a qualification spot in the ICC Cricket World Cup 2015 is something the squad deserves and we're all really happy for them," Clarke said from Sydney.
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Clarke said Afghanistan has not only been a success but an inspiring story.
"Their growth over the past decade as a nation and a cricket side has been an inspiring story to say the least.
"We expect they'll be a challenge for any side in pool A and we're looking forward to playing them on home soil in Perth," he said.