Terrell Owens -- ENDORSING TRUMP ... 'You're Hired!'

Donald Trump's already got his first celebrity supporter ... Terrell Owens ... who tells TMZ Sports he fully supports his former boss' run for the presidency because "he won't put up with B.S."

T.O. -- who appeared on "Celebrity Apprentice" with Trump earlier this year -- says he gained a TON of respect for Trump during their time on the show and thinks D.T. could do great things for the country as the man in charge.

"This may be what the country needs and Trump ... he’s a guy who won’t put up with B.S. and has what it takes to change how government is run."

"With that being said, Trump ... YOU'RE HIRED"

Owens adds, "Plus, as the president, Trump would be able to say he knows me and he likes me ... LOL!"

Terrell says he's got no beef with President Obama -- and thinks he's truly helped change the country for the better -- but says moving forward, he likes Trump.

BTW, earlier this year, Owens appeared on "TMZ Hollywood Sports" and made his pitch for a job in Trump's administration if he's elected. Check it out.