WHAT do comedian Rich Hall, opera singers, the London Firebird Orchestra and Oompah Brass have in common?
They are all joining musical maestro Rainer Hersch at the Southbank Centre for a mash up of music, song and comedy on Easter Monday.
Taking place at the Royal Festival Hall, the April Fools Comedy Concert will be hosted by Rainer and promises a two-hour fun filled musical jamboree for all the family.
The comedian, writer, performer and classical musician will bring his own unique take on a selection of music which he has chosen especially for the occasion.
It will feature star turns from his special guests American comedy legend Rich Hall, Oompah Brass, stars of classical music plus full a symphony orchestra and choir for the afternoon of comedy, music and mayhem.
It is the fourth year running Rainer has brought his April Fool show to the Southbank Centre and comes hot on the heals of his sell out Yuletide show last year.
"That was amazing," he says. "It was the first Christmas one I have done and it was brilliant fun - a sell out, full of people wearing antlers and festive hats - I've never seen anything like it!"
But now he's in the middle of rehearsals for his legendary April Fool's show, though admits it's a bit late in the month to be holding it.
"Easter is really late this year and April Fool's day actually was on a Tuesday so perhaps not the best day for families to come along," he says by way of an explanation.
"This is a family show and in the end it seemed a good idea to do it on Easter Monday.
"We are in the middle of rehearsals and it's pretty amazing so far."
And he says he's very excited not least because he'll be on the RFH stage, which he loves, with "loads" of people.
"It's the biggest concert I've ever done," he laughs. "As usual I oversee everything and this time I've got a 170-piece orchestra, a 72-piece choir plus the extras so it's pretty mega.
"I love the RFH - it's the best concert hall in London and probably the country as far as I'm concerned.
"It's the perfect place to do a concert like this and I'm very excited to be back.
"There's a great line up too so I know the audience will have a brilliant time - it doesn't matter if you are a music professor or couldn't tell a string quartet from a string vest, this is the show for you.
"It will be a guaranteed laugh every four bars. It's going to be very, very funny."
Music-wise, this year the concert will feature Queen's Bavarian Rhapsody, fictitious composer, PDQ Bach's Missa Hilarious, Rossini's Largo al factotum (translated), Rich Hall as Otis Lee Crenshaw and much, much more.
But don't expect any of the original versions.
"As with all my shows, it's a completely different interpretation that the audience will hear," he says. "For example the Oompah Brass band will do chart hits in an oompah style and it will be like nothing you've heard before. I'm really looking forward to their bit because it's utterly brilliant."
And he says working with comedic legend Rich Hall has been fantastic.
"Rich Hall is the comedian's comic," he says warmly. "He's so, so funny but he's also very musical and has released several albums.
"He has a spoof character, a Dixie country singer called Otis Lee Crenshaw who plays a guitar. We have taken some of his songs and scored them for an orchestra which he will be performing with our 170-piece orchestra as a sort of backing band. In between all of this he does his stand up so it's quite something."
As a piece de resistance he has the Queen coming in to do a rendition of God Save The Queen.
"It's not the real Queen of course," he laughs. "Last year we had her parachute in as a homage to the Olympics. This year of course she has a new grandchild, heir to the throne, so I've written a special version of God Save The Queen which will be hilarious.
"There's a lot happening! And it will all be done in my own inimitable style," he chuckles.
April Fools Comedy Concert takes place at the Royal Festival Hall at 4pm on Monday, April 21. Tickets from £9.50. Call the box office on 020 7960 4200.