DUBAI (Reuters) - U.S. contract oil and gas driller Helmerich & Payne (H&P) will invest $100 million in the initial public offering (IPO) of Abu Dhabi National Oil Company’s drilling unit, the companies said in a joint statement. The cornerstone investment by H&P will be at the IPO price and is subject to a three-year lock-up, ADNOC and H&P said in the statement. The deal is part of a strategic alliance, the companies said, that will also see ADNOC Drilling acquire eight land rigs from H&P for $86.5 million. ADNOC, which supplies nearly 3% of global oil demand, earlier this week announced its intention to offer a 7.5% minority stake in ADNOC Drilling through an IPO and subsequent listing on the Abu Dhabi Securities Exchange. Investment bank Moelis & Co acted as exclusive financial advisor to ADNOC, while Morgan Stanley & Co. LLC acted as exclusive financial advisor to H&P. Reporting by Hadeel Al Sayegh; Editing by Emelia Sithole-Matarise Our Standards: The Thomson Reuters Trust Principles.