Actor Neil Patrick Harris has been treated to a series of early birthday surprises ahead of turning 40 in June (13) after his partner organised a special party for him at the weekend (30Mar13).

The How I Met Your Mother star doesn't mark the milestone until 15 June (13), but his fiance David Burkta got the celebrations started way ahead of time.

In a post, Harris wrote, "My b'day is 6/15. @Davidburtka threw a surprise party for me on Saturday - blown away. I'm now on some lengthy treasure hunt that is unreal."

The actor's adventures continued on Monday (01Apr13) as he was driven to Las Vegas, where he joined the performers from Cirque Du Soleil for a training session, and then he hit the road again - this time, by train - as they headed to another mystery location.

He tweeted on Tuesday (02Apr13), "I've dug up locked boxes, driven to Vegas, trained with @Cirque folk, eaten amazing food, and now am on a train to ?? @Davidburtka rules!"

The couple, who stopped at a casino in Laughlin, Nevada for a little gambling before boarding the train, is now on its way to Albuquerque, New Mexico.