The Van Gogh Museum experts said on Tuesday, they now believe that one of Vincent van Gogh's paintings that was earlier thought to be a self-portrait actually depicts his brother, Theo.

If this turns out to be true, this would be the only known painting of Theo, although several sketches of Theo had been made by Van Gogh of his brother. Theo is known to have supported him financially and was his lifelong confidant and friend.

People have often thought it was funny that there were no portraits of Theo, given that they were so close, said museum spokeswoman Linda Snoek, according to an AP report.

She said the portrait was made in 1887 while the brothers lived together in Paris. This period of Van Gogh's life is lesser known to the public. The major part of information about Van Gogh comes from the letters he sent to Theo.

The painting was in the storage for long time and it went on display at the museum in Amsterdam on Tuesday as part of an exhibition on new findings about the painter's time spent in Antwerp and Paris in 1885-1888, according to the report.

Though there is a very obvious resemblance between the brothers physically, scholars say that the painting represents Theo by a number of factors.

Head researcher Louis van Tilborgh compared two paintings from 1887 with similar-looking men in suits set against a blue background.

They are two small, detailed portraits that when you see them you think: they belong together, Van Tilborgh said in an interview with Dutch state broadcaster NOS.

The portrait of Theo shows rounder ears than Vincent's. However, another portrait of Vincent shows him with long, angular ears, consistent with other artists' paintings of him. That's before he famously self-mutilated one of his ears in December 1888, says the report.

Van Gogh suffered from depression and mental anguish much of his life. He shot himself in a wheatfield in 1890 and died shortly thereafter.