Softbank Corp, Japan's No.3 wireless carrier, said it will add to its lineup its first phone using Google Inc's Android operating system in the spring, following similar launches by NTT DoCoMo and Verizon Wireless.

Softbank CEO Masayoshi Son declined to say on Tuesday who will manufacturer its Android phone, but said the phone would feature an OLED (organic light-emitting diode) screen and that it had yet to go on sale.

Softbank's low-cost rates and aggressive marketing campaign have won users away from Japan's biggest carrier NTT Docomo Inc and No.2 KDDI Corp, and it said it will step up its marketing efforts even further to grow in a shrinking market.

Its popular commercial series, made by Dentsu and featuring a family headed by a talking dog, will include a new character played by film director Quentin Tarantino.

Tarantino, whose films include Reservoir Dogs, Pulp Fiction, Kill Bill and Inglourious Basterds will appear as the talkative uncle in the Japanese family.

Softbank, the sole supplier of Apple Inc's iPhone in Japan, hopes to win more users with its new phone lineup equipped with Wi-Fi and touch screens, including one Sharp phone featuring illustrations of Sanrio's Hello Kitty.

NTT Docomo's CEO Ryuji Yamada, who also unveiled Docomo's year-end product lineup of 19 new handsets on Tuesday, said he had not given up on supplying iPhones.

Docomo included into its lineup a smartphone made by South Korea's Samsung Electronics Co for the first time, as well as phones featuring Nissan Motor Co's scratch-shield paint.

Shares in Softbank closed up 2.1 percent, while Docomo closed down 2 percent.

(Reporting by Mayumi Negishi)