Morgan, who has scored 107 goals in 169 international appearances for the United States, was unable to say how long she would be at the club.
Women’s Super League: Tottenham snap up US striker Alex Morgan in remarkable coup as American influx continues
In the WSL, Morgan joins USWNT teammates Rose Lavelle, Sam Mewis, Tobin Heath and Christen Press. The Americans have moved to England looking to get in peak form ahead of next year's rescheduled Tokyo Olympics.
Tokyo Olympics 2020: Christen Press, Samantha Mewis score braces against Costa Rica as United States finish top of group in qualifying
The World Cup-winning US team extended their unbeaten streak to 26 games. The Americans wrapped up the group stage with three shutouts and 18 goals
Carli Lloyd scores twice to help US Women's National Team hold off Sweden in Vlatko Andonovski's first game as coach
Playing without some of its most high-profile players, including Megan Rapinoe and Alex Morgan, USWNT beat Sweden thanks to Carli Lloyd's brace in coach Vlatko Andonovski's first game in charge.
FIFA Women's World Cup 2019: Ali Krieger, Allie Long, Morgan Brian make the cut for defending champions United States' squad
Krieger started for United States against Belgium on 7 April, her first appearance since an exhibition against Russia on 6 April, 2017. It will be the third World Cup for the 34-year-old right back, who has 99 international appearances