Surrey batsman Jason Roy has signed a short-term deal to play for the Sydney Thunder in the Big Bash League.

Roy arrives at the Thunder as a replacement for Eoin Morgan, who will leave the team to link up with England ahead of the Tri-Series with Australia and India.

The 24-year-old, who top scored in the T20 Blast with 677 runs in the competition, admits that he is excited by the prospect of playing alongside Jacques Kallis.

"To be able to play alongside him is going to be an amazing experience and I'm looking forward to picking his brain along the way," Roy told members of the media.

The agreement is for Roy to play three games, and he is set to make his debut for Sydney against the Hobart Hurricanes on January 9.