Tennis star Mark Philippoussis and his teenage girlfriend of five months, Alexis Barbara, are engaged.

Philippoussis proposed to the 18-year-old property tycoon heiress last week when he was in the United States, the Daily Telegraph newspaper reported.

The engagement comes five months after he broke up with Australian singer Delta Goodrem and a month after fellow tennis player Lleyton Hewitt proposed to his girlfriend, actor Bec Cartwright.

Following his split with Goodrem, Philippoussis was romantically linked to hotel heiress Paris Hilton.

Friends of Philippoussis, 28, told the newspaper the engagement had come as a bit of a shock "but Mark is very much in love with Alexis".

"We're all very happy the relationship has gone to the next level," a friend was quoted as saying.

It was understood Australia's Davis Cup players were aware of the engagement, the newspaper said.

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