Sen. Rand Paul (R-Ky.) has endorsed Mitt Romney’s presidential bid, throwing his weight behind the presumptive GOP nominee even as his father, Rep. Ron Paul (R-Texas), has yet to fully terminate his White House bid.

Rand Paul made the move in an appearance on Fox News Channel’s “Hannity."

"Well, you know, my first choice had always been my father. ... He is still my first pick," Paul said, according to a rush transcript of the appearance. "But now that the nominating process is over, tonight, I am happy to announce I am supporting Governor Romney."

In a statement, Romney said that he was “honored” to receive the endorsement of Paul, a freshman lawmaker and founding member of the Senate Tea Party Caucus who is believed to be mulling his own future bid for national office.

“Senator Paul has been a leading voice in the effort to scale back the size and reach of government and promote liberty,” Romney said. “Over the past three and half years, President Obama has made government more and more of a presence in our lives, and Americans can’t afford four more years of the same failed policies. As president, I will reform the federal government and make it smaller, simpler, and smarter.”

The endorsement lends Romney further tea-party backing as he solidifies his support among the GOP faithful.

And it comes as Paul’s father technically remains a candidate in the White House race, although Romney has already clinched the 1,144 delegates necessary to win the nomination.

The elder Paul announced last month that he would suspend his active campaign operation and instead continue his pursuit of delegates through the second- and third-round stages of the nominating process in the states.

While Ron Paul has twice fallen short of clinching the GOP nod, his campaign – which has drawn the enthusiastic support of libertarian-leaning Republicans as well as some anti-war Democrats -- has been viewed in part as an effort to lay the groundwork for a potential bid by his son down the line.

And Ron Paul’s supporters remain intent on making a significant showing at this summer’s Republican National Convention in Tampa, although it remains unclear whether their plans for a “Paul Festival” will be given the green light by convention organizers.