Applause erupted among the party faithful as the 67-year-old cop-turned-telecoms magnate appeared on a sketchy Skype link from an undisclosed country.
Thaksin and his affiliated parties have won every election since 2001, even though he has lived overseas for eight years to avoid jail on a graft conviction.
He is accused of toxifying the country with corruption by the Bangkok-centric royalist elite who have skewered his governments with coups and legal cases, plunging the kingdom into a decade-long political crisis.
Thursday's event was avowedly non-political, in keeping with a ban on political expression under military rule.
Instead, it was billed as a 'cultural event' to celebrate Songkran -- the water festival and Thai new year -- with Puea Thai Party members decked out in bright floral traditional shirts.
"I miss you and I think about you all, especially the people that have fought for the party," Thaksin, who was also wearing a Songkran shirt, said in an address cut short by a poor internet connection.
Puea Thai was booted out from office by the army in May 2014. Thaksin's sister Yingluck -- who was at Thursday's gathering -- was removed as prime minister by the courts a few days before the power grab.
Thaksin was also shunted from office by a coup in 2006.
He has not returned to Thailand since fleeing in 2008 to avoid jail for a corruption conviction he insists was politically motivated.
But his increasingly frequent media forays have infuriated junta leader Prayut Chan-O-Cha.
The Shinawatra clan still draws the adoration of farmers from the north and northeast for recognising their changing social and economic aspirations -- as well as a swathe of the urban middle class.
The Thai junta says it will hold elections in the summer of 2017, once a new graft-busting constitution has been enacted.
Critics of the proposed charter say it embeds military rule and aims to create a straitjacketed democracy, managed by an appointed senate.
"The election will be meaningless if it is based on this constitution," Chaturon Chaisaeng, the education minister in Yingluck's cabinet, told AFP.
"It's a long way off, but I cannot say if we will take part in any election based on this constitution."
Yingluck, Thailand's first female leader, retains support despite also facing jail for negligence linked to a rice subsidy scheme.
And the junta is going to increasingly absurd lengths to muffle support for the Shinawatras.
Last week police seized thousands of red bowls signed by Thaksin distributed in the Shinawatra heartlands for the Thai new year.
A woman who posted a picture with a bowl is also facing sedition charges.