Rocker Rod Stewart risks losing a massive fortune to estranged wife Rachel Hunter after his engagement announcement to girlfriend Penny Lancaster reportedly infuriated her.

Hunter, who had just agreed to an amicable settlement, is now livid that Stewart is getting married again and has allegedly stalled the legal proceedings for their divorce.

The website reported that Hunter had signed a pre-nuptial agreement before marrying Stewart in 1989 that entitled her to around $9.5 million of his $190 million fortune.

But under the law in California, where they both own houses, she could be entitled to half of his wealth, lawyers say. "Rod knows that Rachel might try to get a large settlement from him and he has always been fearful of that but he now has no choice," a source was quoted as saying.

The 60-year-old rock singer had presented supermodel Lancaster a diamond ring, asking her to get married to him, atop the Eiffel Tower in Paris where he had flown her and her family for her birthday.