Help with planning a surprise weekend away please

[Cantdecidewhich]

I have booked to take DP away for a long weekend as a birthday gift but want to keep it as a surprise. Problem I have is he will need the Monday and Tuesday off work and I can't think of a reason to ask him to book it off with out him realising.
Any ideas how I can get round it please?

Can you contact his boss and ask to secretly book it? I've had partners of people who work for me do this

Thanks Sandras it is a huge company and he talks about several different managers. I will try to find out which one it needs to be.
The other thing I am wondering about is we normally go away around his birthday and I know he will start making suggestions nearer the time. I need either an excuse why I can't go away this year or a fake event or something don't I? Blimey this is harder than I thought :)