By Junko Fujita

TOKYO, June 19 (Reuters) - Japan's Nikkei share average hit a record high on Friday as investors scooped up AI-related stocks following a sharp rally in U.S. semiconductor shares.

The Nikkei .N225 was up 0.78% at 71,608.95, as of 0138 GMT, after hitting a record high of 71,952.99 earlier in the session.

The broader Topix .TOPX was down 0.24% at 4,058.54.

"Investors had no choice but to buy chip-related shares after a sharp rally in the U.S. chip shares overnight," said Kazuaki Shimada, chief strategist at IwaiCosmo Securities.

The U.S. Philadelphia semiconductor index .SOX sharply outperformed the rest of the market with a 6.4% rally overnight as Intel's INTC.O shares jumped to a record high and finished up 10.6%.

U.S. President Donald Trump said iPhone maker Apple AAPL.O has agreed to work with Intel to design and manufacture its chips in the United States.

Shares of Intel supplier Ibiden 4062.T rose as much as 5% earlier in the session, and was last up 1.11%.

Fujikura 5803.T was untraded with a glut of buy orders after the fibre optic cable maker raised its annual net profit forecast to 229 billion yen ($1.42 billion).

The AI data-centre materials maker had initially guided for a 156 billion yen profit, just shy of last year's 157.1 billion yen.

"Fujikura raised its forecast at a time when the market turned cautious about the outlook of fibre optic cable makers," Shimada said.

Shares of peer Furukawa Electric 5801.T surged 15%.

Technology investor SoftBank Group 9984.T and chip-testing equipment maker Advantest 6857.T rose 3.25% and 4.19%, respectively.

The Nikkei's gains were limited as investors were cautious about the recent fast-paced rally, Shimada said.

The index closed about 9% above its 25-day average in the previous session, indicating an overheated market, said Wataru Akiyama, an equities strategist at Nomura Securities.

Bank shares dragged the Topix lower, with Mitsubishi Financial Group 8306.T and Mizuho Financial Group 8411.T down nearly 3% each.

($1 = 161.1100 yen)