Gavin Degraw For Dancing With the Stars

Multiple 'DWTS' sources confirm the "Not Over You" singer has signed on for the new season -- the full cast will be announced on Tuesday morning.

Degraw's taking on a major work load -- his current tour continues through mid April ... but the show premieres on March 19th.

We're told Gavin's dancing pro will most likely join him on tour so they can keep practicing -- but none of his tour dates conflict with 'DWTS' airdates.