Rachel Bilson and Hayden Christensen are planning to become man and wife.

The pair are said to have secretly become engaged in December.

‘They're so excited,’ a pal tells People. ‘They're a great couple. Rachel seems thrilled beyond belief.’

Rachel and Hayden, both 27, became an item last year, when they starred together in Jumper.

No wedding date is thought to have been set yet.

‘I don't comment on my clients' personal lives,’ says Rachel’s agent.

Hayden’s rep declined to comment