Thousands of well-wishers, including team-mates and politicians, sent messages of support on Monday to India's World Cup-winning all-rounder Yuvraj Singh, who has been diagnosed with cancer.

Yuvraj is being treated for lung cancer in Boston in the United States. He was diagnosed in October and the disease is in its early stages, his physiotherapist announced Sunday.

Jatin Choudhary said the rehabilitation would be complete by the end of April and Yuvraj would be fit to play in May.

"Wish Yuvraj a speedy recovery! Asking officials to find the quantum and nature of help required. Government should and will help him," Indian sports minister Ajay Maken wrote on Twitter.

India off-spinner Harbhajan Singh wrote on the micro-blogging site that "whatever Yuvraj is dealing with, we need to support him, leave him alone and allow him to recover soon.

"He is a born fighter. I request media to respect Yuvraj's privacy and allow him to concentrate on his recovery. He will be back with a bang."

India skipper Mahendra Singh Dhoni said he did not know about the illness as he has not been in touch with Yuvraj, but he told the Press Trust of India news agency: "He is a pleasure to have in the side."

Left-handed Yuvraj had a dream run in the World Cup, scoring 362 runs and grabbing 15 wickets across nine matches. He earned the Man of the Tournament award.

But his family said in November that the all-rounder had been battling a golf ball-sized non-malignant lung tumour.

Vijay Mallya, who owns Indian Premier League side Royal Challengers Bangalore, said he was "devastated" by the news, while Indian Davis Cup tennis player Rohan Bopanna insisted: "All our prayers and good wishes are with him".

Yuvraj has scored 8,051 runs in 274 one-dayers and 1,775 runs in 37 Tests since making his international debut in 2000.