The couple tied the knot in mid-June, a month-and-a-half before the swimmer extended his record-breaking medals streak at the Brazil Olympics, according to records obtained by TMZ.

Sources claim Johnson became Mrs. Phelps in Paradise Valley, Arizona, and the quiet ceremony was officiated by the swimmer's longtime friend and agent Peter Carlisle.

The couple reportedly filed the Record of Marriage on 15 June (16).

Throughout the Olympics coverage, Johnson, the mother of Phelps' son Boomer, was introduced as the sportsman's fiancee.

The swimming ace caught wind of the marriage story during a Facebook Live chat with fans last week (ends21Oct16) and flatly denied he and Johnson were husband and wife.