But the news came a few days late, as the midfielder was originally scheduled to be included in Thailand's squad for the Asian Cup qualifiers against Lebanon on March 22, which ended in a 5-2 loss for the War Elephants.
The decision by the football governing body overturned an earlier ruling by the Asian Football Confederation [AFC], which declared the former Grasshopper Club Zurich player ineligible for his new country of allegiance.
Chappuis who was born in Kloten, Switzerland to a Thai mother, and started his professional career with Grasshopper in 2009 before he was loaned out to second-tier clubs FC Locarno and FC Lugano.
He signed with Thai Premier League club Buriram United at the start of 2013 and applied for Thailand passport soon after.
Although Chappuis had represented Switzerland in the Fifa Under-17 World Cup in 2009, the player was still eligible to represent another country at a senior level in accordance to Fifa’s Article 18 of the Regulations Governing the Application of the FIFA Statutes under the following conditions:
"He has not played a match [either in full or in part] in an official competition at "A" international level for his current Association, and at the time of his first full or partial appearance in an international match in an official competition for his current Association, he already had the nationality of the representative team for which he wishes to play," it stated.