Having started his career with the Brixton TopCats, Bryan-Amaning now returns to his home city to play with the Lions at their new home in the Copper Box Arena on the Olympic Park.
Macaulay is delighted to add the GB player to his roster, he said: "We're happy to have Matthew on board. He is the premier British baller of his generation.
"The Lions are the new home of London basketball, and it's great to have eight of out ten players from London. The fans will love watching him play."
It is not the first time Bryan-Amaning has played for the Lions; he made a guest appearance earlier this season when they hosted Iowa University in their first game at the Copper Box. He returns on Thursday when the BBL side take on the Worcester Wolves, tip off 19:30.
Tickets available here.