Manchester United have agreed to sell Angel Di Maria to Paris St Germain for 63million euros.
Angel Di Maria is set to undergo a medical with Paris Saint-Germain ahead of a proposed £44m move from Manchester United.
Seaborne has won three and drawn one of the four matches he has played in since making the temporary move to The Valley.
The 25-year-old was forced to sit out the final match of his original loan spell, last Saturday's 2-2 draw against Brighton.
But Seaborne will get the chance to extend his unbeaten run in the Charlton team after a fresh deal was struck.