Nicole Scherzinger is apparently tired of "sneaking around" with Lewis Hamilton.
The on/off couple broke up in July last year but were rumoured to have met in secret since then.
Earlier this month the pair were pictured together in public when they dined out at Italian restaurant E Baldi in West Hollywood.
"Nicole and Lewis have been in contact for months. After meeting several times and discussing their relationship at length, they decided they didn't want to sneak around anymore," a source explained to British magazine Star.
"It was a special occasion, so they decided to go out together and let everyone know they are back together. It couldn't stay a secret forever."
At the beginning of January, Nicole and Lewis sparked rumours they were holidaying in Aspin, US, together when they posted very similar pictures of themselves skiing on Twitter.
The couple have been dating sporadically since 2008 and there was speculation their split was down to 29-year-old Lewis not being ready for marriage and a family with Nicole, 35.
Now they are reportedly ready to put the past behind them and move forward with their relationship.
"The past year has been difficult for Nicole and Lewis, but they're finally in a stable place and looking forward to the future," the insider added.
Recently there was even talk that The X Factor UK judge is ready to live with the Formula One star.
"Nicole is giving serious thought to moving in with Lewis," an insider told British newspaper The Sun.
"Both sets of families are behind them being back together and she and Lewis say it feels right.
"They know they can't keep splitting up and getting back together, so more commitment is the next step.
"After reuniting at Christmas, Lewis has decided he wants Nicole at his side for good."