Gavin Degraw -- Pulls 'Dancing With the Stars' 2 Step ... Dancing AND Touring At the Same Time

Gavin Degraw is up for some serious double duty -- he's joining the cast of "Dancing With the Stars" ... but TMZ has learned he will also continue his current U.S. tour.

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 -- the show premieres on March 19th ... but his tour continues through mid April.

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.