Pitbull SHOCKED By LiLo Suit -- I Was Trying to Keep Her Relevant

Rapper Pitbull thinks Lindsay Lohan should be thanking him -- not suing him -- for including her name in his hit song, "Give Me Everything" ... claiming he thought the shout-out would HELP her career.

Pitbull went into serious mode during an interview for his official fansite -- wearing a suit and tie -- and said, "I was very surprised when I found out about the lawsuit ... at first I read it and I thought, 'This has got to be a joke.'"

As TMZ first reported, Lohan filed the suit last week -- claiming the rapper wrongfully used her name for commercial gain by using the lyric, "I got it locked up like Lindsay Lohan" in the song.

The rapper says he supports Lindsay's career -- adding, "In no way shape or form would I wanna bring that on anyone ... I didn't look to defamate [sic], degrade or hurt someone's career."

"For me mentioning it ... on the number one record in the world ... I thought it would be helping someone's career and keeping them relevant."