MLS expansion franchise Philadelphia Union have officially sold out of season tickets.

After overwhelming popularity, Union fans have purchased 12,000 season tickets and supporters can now only get a limited number of partial plan tickets.

The response from the Philadelphia public was warmly welcomed by Union CEO Nick Sakiewicz.

"When we embarked on this journey 4 years ago we quickly found out that the Greater Philadelphia region had a robust and passionate soccer fan base," said Sakiewicz. "The fact that we've sold out of season tickets to all Philadelphia Union games so far in advance of our first game at PPL Park is a testament to that fact and we continue to work hard to serve our fans."

The Union are currently based at Lincoln Financial Field but will soon move to Chester's brand new PPL Park, which president Tom Veit said was an exciting prospect.

"We would like to thank the fans for the great support that they have shown us over our two games at Lincoln Financial Field," said Tom Veit. "We averaged nearly 30,000 fans between our two home games, which is simply amazing, and we look forward to sell out crowds at PPL Park."