Dean Martin got an unexpected birthday present Wednesday night in Las Vegas--a surprise visit from his old partner, Jerry Lewis. "Here's to 72 years of joy you've given the world and why we broke up, I'll never know," Lewis told Martin as he walked on stage at the end of Martin's performance at Bally's Hotel and Casino on the Las Vegas Strip. "You surprised me," responded an overwhelmed Martin. "I love you, and I mean it." The two embraced, traded banter, then hugged again. The famous duo from the 1940s and 1950s have rarely appeared together since they split up in 1956.