David Hasselhoff has proposed marriage to Simon Cowell's longtime girlfriend Terri Seymour.

The shocking proposal came as part of a 12-hour reality TV experiment staged by the TV news show Extra, during which Seymour had to spend a night locked in a Las Vegas hotel room with the former Baywatch star. The 'lockdown' took place in a luxury suite at Planet Hollywood's Resort and Casino. The pair played videogames, board games, enjoyed naked massages together and hosted guests including illusionists Penn & Teller and comedian Carrot Top.

Seymour and Hasselhoff also chatted with the actor's fans via his official website www.Hasselhoff.com. But a big surprise came when Seymour realized her roommate, who works for her music mogul boyfriend Cowell on hit show America's Got Talent, asked her to marry him.

The TV experiment, complete with proposal and Seymour's reaction, will air on Extra for three nights, beginning on Tuesday.

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(This news article provided by World Entertainment News Network)