The event, to be held at Rotunda, Green & Fortune's Kings Place restaurant, will kick off at 12.15pm on 15 March.
Guests will be greeted with canapés and a Black Velvet - a cocktail of Champagne and Guinness - followed by a four-course lunch inspired by Irish cuisine, paired with a selection of wines.
Hospitality recruitment company Troika is sponsoring the event by providing the welcome drinks and wines.
As well as live music throughout the day, a raffle and an auction will raise funds for the two charities. Prizes will include a trip for two to Amsterdam, with travel on Eurostar and a weekend stay at Art'otel Amsterdam.
Founded in 2010, the Clink works in partnership with Her Majesty's Prison and Probation service to provide training programmes in prisons across the UK, giving inmates the skills needed to secure work in the hospitality industry after release.
The Clink now operates four restaurants, three kitchens, two gardens and an event catering business, all of which are based in UK prisons and staffed by inmates. The charity has trained more than 1,800 serving prisoners to date.
Green & Fortune chief executive John Nugent employed the first ever Clink graduate with the help of Troika.
The London Irish Centre, based near Kings Place, works to create a hub of culture and support for London's Irish community, with an outreach programme to provide care for those in need. The centre also promotes Irish heritage with a programme of regular events and workshops.
Nugent said: "We should always take time to reach out to our charity friends and partners to assist where possible. We work in a sector that is known for its generosity in supporting great charitable causes. I am delighted that Green & Fortune and Rotunda are working with both the London Irish Centre and the Clink to raise vital funds. It will be a fun day with great longer-term outcomes for these fantastic charities."
Tickets at shared tables cost £95 per person. Tables of 10 can be purchased for £900 including VAT. Tickets and tables can be reserved by visiting the website at http://www.rotundabarandrestaurant.co.uk/product/celebrate-stpatricks-day/ or by calling Rotunda on 020 7014 2840.Get The Caterer every week on your smartphone, tablet, or even in good old-fashioned hard copy (or all three!).