NetApp (NTAP) this afternoon announced that it will acquire Data Domain (DDUP) for $25 a share in cash and stock, or $1.5 billion net of DDUP’s cash position. The announcement did not give details on the terms of the deal, which comes at a substantial premium: DDUP closed today at $17.93, up 50 cents, or 2.9%.

Data Domain provides de-duplication storage systems.

The company said it will provide details on the deal on its earnings conference call this afternoon.

Update: On the call, NTAP CFO Steve Gomo said each DDUP share will be exchanged for $11.45 in cash and 0.75 NTAP shares. In all, 47 million shares will be issued in the deal. The cash portion will be financed with cash on hand. The deal is expected to close in 60-120 days. The company expects the deal to be accretive to non-GAAP earnings within 12 months.