Evan Rachel Wood and Jamie Bell are thought to be tying the knot after they collected a marriage licence on Tuesday.
The pair, who met when filming the music video for Green Day song Wake Me Up When September Ends, were seen picking up the license in Beverly Hills.
An onlooker said: "Evan and Jamie were at the Beverly Hills City marriage licence office around lunchtime.
"I had to do a double take as at first as I didn't recognise them. They looked like any other young couple in love.
"They were just waiting in line like regular people, holding hands and at one point Jamie leaned over and kissed Evan - they certainly looked excited and happy!"
The pair split up in 2006, but were thought to have rekindled their romance last year.
Image: © Getty