Myanmar has released Zarganar, a prominent comedian and dissident, as part of an amnesty for thousands of prisoners that is expected to include a number of political detainees.
Ma Nyein, Zarganar's sister-in-law, told AFP news agency: "I have talked to him. He is free now."
Myanmar's President Thein Sein had on Tuesday signed an order to free 6,359 inmates who are old, disabled, unwell or who had shown good "moral behaviour".
Reports suggest that there have been at least 300 political prisoners among those released so far.
Aung San Suu Kyi, the Myanmar opposition leader, said " We hope many more will be released...I'm really thankful for the release of political prisoners."
Zarganar was detained in 2008 after giving interviews to foreign media criticising the nation's former military rulers for being slow to respond to Cyclone Nargis, which left nearly 140,000 people dead or missing.
He was convicted of causing public alarm and illegally giving information to the press.
Freedom for political detainees has been anticipated as part of liberalising measures since Myanmar's long-ruling military government handed power in March to a military-backed civilian administration.
Estimated at 2,000, political detainees include journalists, pro-democracy activists, government critics and monks involved in anti-government protests in 2007 and members of Burma's ethnic groups fighting for greater autonomy.
Altsean Burma, a human rights organisation, cautiously welcomed the prisoner amnesty, with Debbie Stopard their spokesperson, telling Al Jazeera: "We need to see reforms not just based on the release of prisoners but a cessation of military influence as well."
Nyan Win, a spokesman for Suu Kyi, said: "We welcome the amnesty announcement. This is very good news and we hope that many political prisoners will be among those freed."
Relatives of political detainees were excited by the announcement, but wary, given that they could not be sure who would be among those released.
Thein Sein instituted an earlier amnesty soon after taking office, but it included just a few dozen political detainees.
Justin Wintle, author of the Perfect Hostage, told Al Jazeera the release is aimed at convincing western powers to ease sanctions.
"Things have been changing in Myanmar. There is a new guy at the top. But the question is whether he is just a pragmatist or is he genuinely committed to reform. There are signs: he had a face to face meeting with Aung San Suu Kyi, something that his predecessor had resolutely refused to do.
"I think the Burmese government is fairly committed to seeing if they could have sanctions-European and American-lifted. And I think there is a mood change there."
Hillary Clinton, the US secretary of state, said her country was encouraged by "promising signals" of political reform in Myanmar, but it is too early to announce steps Washington might take in response.
In an interview with Reuters news agency on Tuesday, she said: "We want to see actions. If they are going to release political prisoners, that would be a very positive sign."
The release of political detainees has been a key concern of the US, which has been seeking to re-engage with Myanmar after isolating its former military government with political and economic sanctions over its poor record on human rights and democracy.