Top Gun
In the iconic scene from classic film Top Gun, Charlie (who is played by Kelly McGillis) admits that she has feelings for Maverick, played by none other than Tom Cruise. Charlie makes it clear that she does not want anyone to know about her feelings, when suddenly Maverick kisses her.
Maverick and Charlie
The passionate kiss was not scripted, and was due to a funny reason. Tom Cruise actually forgot his lines, and had the idea that a kiss would speak volumes, so he went for it. The director ended up keeping the unscripted kiss in the final take, and the rest is history.