In his divorce filing in Los Angeles, the actor cited "irreconcilable differences" as the reason, according to TMZ. Since the duo doesn't share children and had an ironclad prenuptial agreement, the divorce is expected to be fairly cut and dry.
The date of the separation is listed as "TBD."
The formal divorce filing comes less than two weeks after the couple announced that they had separated.
Liam is "over the marriage" and just wants to move on, TMZ said, adding that Miley supposedly made overtures as recently as this week, saying she wanted to work on the marriage. Liam, however, was ready for it to simply be done.
The divorce filing might be seen as somewhat of a surprise, as just last week E! News said Miley and Liam's families wanted the duo to hold off before doing anything drastic.
"Their families have urged them to take some time to breathe before they make any final decisions," a source told E! "They are both upset about how this has blown up and are both hurting right now."
Miley and Liam's 10-year relationship has seen lots of ups and downs, including called off engagements and new relationships. They later reconciled, got engaged in 2016 and tied the knot in December 2018.
A source told People magazine of Miley and Liam, "They're not on the same page when it comes to a lot of fundamental things that make a relationship work."
Said E!'s source, "Their relationship completely changed. … Miley got back in the studio and was focused and serious about her new music."
Since the split, Miley dropped a new song, "Slide Away," that seems to be all about the end of her marriage. In addition, Miley was recently photographed passionately kissing Brody Jenner's ex, Kaitlynn Carter, in Italy (Liam was said to be "devastated" over the pictures.) The women were spotted making out again this week in Los Angeles.