Liam Neeson's thriller "Unknown" has shocked movie industry experts by beating action film "I Am Number Four" to the top of the box office.
The closely contested race ended with Neeson's new film, in which he plays a botanist who ceases to exist in the eyes of his family and colleagues after a car crash, scoring a $21.8 million opening weekend - $2 million more than second-placed "I Am Number Four," which stars "Glee's" Dianna Agron and Brit Alex Pettyfer.
"Unknown" beat most projections by $3 million.
Animated comedy "Gnomeo & Juliet" was just behind in third with $19.4 million, taking its two-week tally to just over $50 million.
Comedies "Just Go With It" and "Big Mommas: Like Father, Like Son" round out the new top five.
Watch "Unknown tops box office, Gaga an iTunes favorite"