The Black Eyed Peas had a hit with "I Gotta Feeling."

The songs is a catchy tune, that has been popular in
dance clubs around thew world.

This song is interesting for learning English because of
its strange use of grammar.
The title "I gotta feeling", is a mistake. It comes from
the idea of I've got, which is a slang way to show
possession.

Possession is shown with the verb HAVE.
EX:        I have a dog.

In conversation, it is common to use the informal I'VE
GOT.
Ex:        I've got a dog.

This can be reduced further to I GOT.
Ex:        I got a dog.

However, the Black Eyed Peas use the wrong form of
this slang for possession. They have used GOTTA,
which is slang for HAVE TO, or MUST.
Ex:        I have to work tomorrow night. ---> I gotta
work tomorrow night.

So, the title "I Gotta Feeling" is incorrect because it
means I have to feeling.

However, don't let a grammar mistake stop you from
enjoying the song. Here is the video with the lyrics.

I Gotta Feeling - Black Eyed Peas