The 31-year-old two-time World Cup winner is the latest in a long line of United States women's national team players to join the Women's Super League with Sam Mewis and Rose Lavelle joining Manchester City and Tobin Heath and Christen Press signing with Manchester United.
"2020 is the year of the unexpected, but next up -- the first stamp on Charlie's passport," Morgan tweeted about the move.
Sources told ESPN on Friday that Morgan's contract runs through the final four months of the calendar year but also contains an option to stay at Tottenham through the end of its season in May.
Morgan previously played in Europe with Lyon during the second half of the 2016-17 season. However, her season was marred by injuries which limited the amount of time she spent on the pitch.
She started her career with Western New York flash in 2011 when she was drafted as the number one overall pick. She went on to play with Seattle Sounders and won the National Women's Soccer League title with Portland Thorns in 2013.
She joined Orlando Pride in 2016 but hasn't appeared for the side since giving birth to her daughter Charlie in May.
"We understand and support Alex heading to England in order to obtain more match and training opportunities," Pride head coach Marc Skinner said in a statement. "Returning to play has been a long time coming for Alex and, as a player that is looking to not only get back to match fitness but also compete for an Olympic roster spot, the additional months of games and training beyond the NWSL's Oct. 17 end date is right for her."
Morgan has 169 international caps and won a gold Olympic medal with the USWNT in 2012. During that time she has scored 107 goals and grabbed 43 assists.
She was training with the national team prior to the cancellation of the Olympics while seven months pregnant.
As an allocated player in the NWSL, her league salary is paid by U.S. Soccer, and there is no transfer fee due to either the Pride or the U.S. federation.