NEW YORK — Less than 24 hours before the boards of CBS and QVC were expected to vote on, and approve, a merger arrangement, cable-service provider Comcast Corp. butted in with a $2.2 billion cash and stock bid for Barry Diller’s home shopping network.

The $44-a-share bid from the Philadelphia-based firm came late Tuesday in a letter delivered to QVC chairman Barry Diller. In it, Comcast chairman Ralph J. Roberts and president Brian L. Roberts say “the proposal to sell QVC to CBS is of great concern to us as it represents a fundamental departure from our strategic view of the company’s future.” The letter begins by noting Comcast was a founding shareholder of QVC. It currently holds a 16.6-percent stake.

The bid is a 22.2 percent premium above QVC’s Tuesday closing price of $36 in over-the-counter trading.

“All ironies aside, I said at the outset that if someone else wanted to bid for QVC, we would, of course, deal with it. And we will, with the only consideration being the best interest of the QVC shareholder,” Diller said in a statement.

The CBS acquisition of QVC was expected to include the installation of Barry Diller in the top spot at the combined operation.