Traveling to Ireland for an interview

[rich]

Hi - I hope you can help.

I work for a large company who is based in the UK. I am trying to arrange to fly a candidate in to Dublin for a couple of days so that he can attend a day of interviews and also have a look around the city.

The candidate is Indian but is married to a EU citizen and lives in Switzerland.

I understand that he will need to sort out a visa for the visit. Will he need a letter of invitation as well?

Any information or help would be gratefully received!