(CNN) - Donald Trump isn't monkeying around with Bill Maher.
The real-estate guru is suing the talk show host for $5 million.
It all spawns from a joke Maher made about Trump on Jay Leno's "Tonight Show" last month, saying he would fork over 5 million to charity if the billionaire could prove he wasn't part orangutan.
Trump, in turn, presented Maher with his birth certificate as DNA proof he is 100 percent human.
Now, Trump wants Maher to pay up, citing a breach of contract.
Maher responded with a tweet saying, "What? Really? ha ha ha!"