Blue's Big Musical Movie (2000)
Blue's Big Musical Movie (also known as Blue's Big Musical) is a 2000 American direct-to-video film based on the Blue's Clues television series, and acted as the first full length musical film for the character of Blue the Dog. The film had a theatre premiere on October 3, 2000 and later, its home video release was on October 10, 2000. This movie was reissued on DVD along with Dora the Explorer: Musical School Days on July 23, 2013.
More at Wikipedia.