The entertainment agency, which also handles personal publicity for Barlow, will promote the single as well as a one-off charity gig set to take place in Manchester.
The Children In Need single, released on 13 November, will be performed by a supergroup called The Collective, including big names such as N-Dubz, Ed Sheeran, Wretch 32, Tinchy Stryder, Ms Dynamite and Chipmunk.
The single is a reworked version of Massive Attack's 1998 hit Teardrop.
Dawbell will also promote the Children In Need Rocks concert on 17 November in Manchester. The show is set to feature performances from Lady Gaga, JLS and Barlow himself. In 2009, Barlow organised the Children In Need Rocks concert at London's Royal Albert Hall, where he was reunited on stage with Robbie Williams for the first time in 15 years.
Meanwhile, TV personality James Corden has appointed Dawbell to handle his personal publicity.