Kate Middleton

The big question this year is what Kate will wear - and if she'll recycle that classic green coat again.

For the last two years, the Duchess of Cambridge has shown she's green in every sense and recycled an emerald outfit to attend a St Patrick's Day military parade.

The expectant Duchess dressed her bump in an Emilia Wickstead dress coat both years, bought especially for the occasion.

She teamed the forest-green outfit with an updo and black hat, tights and trademark black heels last year.

But she almost came a cropper after getting her stiletto stuck in a drain, grabbing onto William for support.

We know she loves to re-use those stunning clothes, but perhaps it's time for a change this year.

Rex

We may see a change of shoe this time around to prevent that happening again.

Prince William wore full ceremonial uniform last year as Colonel of the Regiment, and is expected to do the same again.

The presentation of shamrocks by a senior female member of the royal family is a century-old tradition which was started by Queen Alexandra, the wife of Edward VII, in 1901.

The role was famously carried out by the Queen Mother.