"My heartiest congratulations to former Prime Minister Mannmohan Singh for being honoured with Japan's second highest civilian honour, the Grand Order of the Cordon of Paulownia Flowers," Gogoi tweeted today,
"Your achievement has made us all very proud, more so because never before such an honour has been bestowed on an Indian," he added.
Singh and his wife Gursharan Kaur is currently on a three-day visit to Tokyo where he will be given the award by Japanese Emperor Akhito.
Singh is a Rajya Sabha MP from Assam.