"Gavin's thrilled with what's happened now," said his agent Matt Ginvert.
"Gavin's totally committed to see through Strictly Come Dancing and to do his best to win if he can.
"He's really looking forward to getting back on the rugby pitch when he is available to do so."
Henson hasn't played since March 2009 after taking unpaid leave from the Ospreys following a spate of injuries.
The Wales centre was still under contract with the Liberty Stadium outfit until the end of this season but he made it clear last month that he wanted to play rugby in London in order to be in a new environment and to be nearer his children.
The Ospreys have now reluctantly agreed to release Henson from his contract, with Saracens set to formally announce the signing at a press session later today.
"I am disappointed and frustrated, both personally for myself and for the Ospreys, as one thing we would all want to see is Gavin Henson back in an Ospreys shirt," said the Ospreys' managing director Mike Cuddy.
"All rugby fans will look forward to seeing Gavin back on a rugby pitch, and we sincerely hope that he will be back in the red jersey of Wales before too long.
"With the Rugby World Cup taking place next year, no doubt that will be the focus of Gavin's efforts over the coming months.
"As a rugby organisation, we pride ourselves on our contribution to the national set-up and we strongly believe that we would be the best place for Gavin to launch his return to rugby and to target a place in the Wales squad.
"However, as frustrating as it is for everyone involved at the Ospreys, on this occasion we have to concede that he will not play for us during the remaining time on his contract, and as such, take the responsible course of action that is best for all concerned."